CLASSIFICATION, NATURAL HISTORY, AND EVOLUTION OF THE GENUS APHELOCERUS KIRSCH (COLEOPTERA: CLERIDAE: CLERINAE)

Abstract The genus Aphelocerus is redefined to include 66 species as follows: A. leucomelas (Chevrolat); A. coalitus, n.sp.; A. echinatus, n.sp.; A. affaniatis, n.sp.; A. delicatulus (Barr); A. aeneus, n.sp.; A. bispineus, n.sp.; A. extensivus, n.sp.; A. primigenious, n.sp.; A. ciliaris, n.sp.; A. acuticolis, n.sp.; A. citimus, n.sp.; A. sturnus Kirsh; A. acanthus, n.sp.; A. inconstans (Gorham); A. cirritus, n.sp.; A. patulus, n.sp.; A. chiriqui, n.sp.; A. sculptilus, n.sp.; A. sabulosus, n.sp.; A. chondrus, n.sp.; A. cohibilis, n.sp.; A. irroratus, n.sp.; A. immarginatus (Chevrolat); A. acutus, n.sp.; A. torosus, n.sp.; A. olanchoensis, n.sp.; A. vietus, n.sp.; A. turnbowi, n.sp.; A. cornuatus, n.sp.; A. humerus, n.sp.; A. domus, n.sp.; A. capillus, n.sp.; A. coactus, n.sp.; A. scalenus, n.sp.; A. yungas, n.sp.; A. extensivus, n.sp.; A. lividus, n.sp.; A. nitidus, n.sp.; A. sagittarius, n.sp.; A. triangulus, n.sp.; A. batesi, n.sp.; A. ebenus, n.sp.; A. catie, n.sp.; A. monteverde, n.sp.; A. arenatus, n.sp.; A. bufustis, n.sp.; A. anticus, n.sp.; A. naevius, n.sp.; A. protenus, n.sp.; A. argus, n.sp.; A. panus, n.sp.; A. hespenheidei, n.sp.; A. collaris, n.sp.; A. dispilis, n.sp.; A. formicoides, n.sp.; A. akis, n.sp.; A. chelonus, n.sp.; A. cheliferous, n.sp.; A. scutellaris (Chevrolat); A. improcerus, n.sp.; A. propinquus, n.sp.; A. calvus, n.sp.; A. myrmecoides, n.sp.; A. inbatus, n.sp.; A. eriodes, new species, and A. discapillus, new species. Lectotypes have been designated for A. inconstans, A. leucomelas, A. nitidus, and A. immarginatus, and for the junior synonyms Clerus laevigatus Spinola, C. mollifascia Chevrolat (new synonymy), C. subfasciatus (Chevrolat), and C. cyaneus (Chevrolat) (new synonymy, new combination; transferred from Enoclerus Gahan). Aside from the conventional subject categories of generic revisions, this work also includes a translation of the abstract into Spanish, a treatise about natural history, discussions of species groups and troublesome key couplets, and evolutionary considerations involving phylogeny and zoogeography. There are 28 habitus illustrations, 239 line drawings, 29 distribution maps, 9 maps depicting the distribution of the major New World clerofauna, 13 electron micrographs, 5 photographs, 1 phylogenetic tree generated by the Hennig 86 computer program, a table involving character analysis, and a table depicting the geographical distribution of the apheloceran species groups. Members of the genus Aphelocerus are thought to be involved in a mimetic complex that also includes species of ants, buprestids, and chrysomelid beetles, weevils, and spiders. These checkered beetles have been observed to scurry on broad-leafed herbaceous plants, and particularly along leaf stems, often in the company of black ants of approximately the same size. A few have been observed foraging on a variety of tree canopy blossoms, although it is not known whether the clerids were consuming anthophilic insects or taking nourishment from flower products such as nectar or pollen. Specimens have been collected throughout the year; however, most were captured from May to July, at elevations ranging from 97 to 3000 m. The “beating sheet” method of collecting seems to be the most productive manner of gathering these beetles, although specimens have been collected with an aspirator while the insect was scurrying on foliage or bark (fig. 1b). Other collecting techniques that yielded specimens include the use of sweep nets, light traps, and Malaise traps. A few specimens were aspirated from flowers of forest trees. It is postulated that the initial division of ancestral Aphelocerus occurred on the current land mass geologically formed by the union of the Mexican/Mayan blocks. The evolution of the group probably began some time after the major Caribbean tectonic events had taken place. The relative paucity of structural diversity among the extant members of the genus suggests a recent evolution for the group or strong selection to resemble a common model for mimicry. The available evidence indicates that there have been three major evolutionary trends among the extant species of Aphelocerus. The first involves the progressive increase of elytral convexity among the mimetic species of the genus, i.e., mimicry of ants, spiders, and Myrmex weevils. The second trend involves the development of white secondary (2°) setae on the elytra, and third, the consolidation of these setae into white setal patches on various organs of the integument. The prominent association of checkered beetles with temperate and tropical montane regions suggests that checkered beetles, in general, occur in seven New World geographical areas, each of which is illustrated: North America, Middle America, South America, Mexo America, Central America, Nuclear Central America, and Insular Central America.


INTRODUCTION
My familiarity with these tropical beetles began during an expedition to Tabasco in southeastern Mexico during the summer of 1971. There, alongside a patch of deciduous forest, I noticed a small population of what I thought were black ants scurrying on leaves and twigs of a woody shrub locally known as ''Jobo' ' (fig. 1a). Upon closer examination, I realized that I had come upon a bonanza of checkered beetles, a relatively rare collecting experience that I came to appreciate over the years compared to the usual frustration associated with the collecting of these beetles in increments of one.
Further, it was unfortunate that at the time of that collecting experience I did not realize that before me was an opportunity to investigate a question that still perplexes coleopterist colleagues, why are there so many little black insects and spiders that have silvery hair tufts along their flanks? Over time, it became apparent that aphelocerans are components of a large mimetic complex that involves very distantly related insects and at least one species of spider. Accordingly, I began to collect insects with fascies approaching aphelocerans. Also, I searched in prominent collections and found specimens of A. myrmecoides, n.sp., among Myrmex weevils and vice versa. In the process of beating oak branches, I gathered buprestids, chrysomelids, and cerambycids that belong to the aforementioned mimetic complex. Unfortunately, our state of knowledge about the biologic implications of these mimetic similarities is minimal and invites only tentative explanatory speculations. It is hoped that the comments in this contribution will encourage more extensive field observations and experimentation that will shed more light on this fascinating aspect of checkered beetle biology.

MATERIALS AND METHODS
This study is based on more than 1000 adult specimens borrowed from museum and private collections, or collected by me during fieldwork. I observed living aphelocerans in Mexico, Guatemala, Nicaragua, Costa Rica, and Panama. Live specimens of these checkered beetles were placed in killing jars with cyanide or ethyl acetate, then immersed in Pampel's to facilitate investigations of internal anatomy. Investigations of the digestive system organs and those of the internal reproductive system continue to produce variations useful particularly for studies of supraspecific systematics.
During the initial stages of the classificatory process, I first sorted specimens according to geographic origin, and then severed the abdomen from all male specimens to determine the extent of structural variation of the pygidium and aedeagus. Abdomens were easily separated from pinned beetles, but point-mounted specimens had to be relaxed in a warm soapy water solution, and then dissected under water. In time, I devised a more efficient method of gaining access to the genitalia of dry, point-mounted specimens as follows: Abdomens were severed from dry specimens by first removing the pin from the paper point, then the beetles, while still attached to the paper point, were placed upside down onto an inverted pinning tray matted with very soft tissue paper. Next, a number three pin was used to dislodge the abdomen from the thorax by piercing the abdomen behind/beneath each metacoxa. Some specimens were soaked and cleaned with a sonic cleaner, then dried and repinned. Severed abdomens were then subjected to a solution of warm KOH that facilitated the extraction of the aedeagus, ovipositor, and pygidium. The best results were obtained when the dry abdomens were immersed overnight in a 25% cold solution of KOH. Female abdomens were similarly treated when the pygidium and/or sixth visible abdominal sternum showed noteworthy variations.
Techniques of illustration and measurements were similar to those I described in my works of Perilypus (Ekis, 1977: 6) and Plocamocera (Opitz, 2004: 7). Within descriptions there are numbers in parentheses separated by a colon. These numbers represent measurements intended to provide dimensional ratios between structures that are being compared. Standard anatomical terminology used in this work originates from Nichols (1989). I recognize that the plate that constitutes the visible venter of each abdominal segment in beetles represents a portion of the ''real'' segmental sternum. As Snodgrass (1935: 78) indicates, ' '. . . in the abdomen the sternal plates appear to contain, in most cases the entire basal parts of the otherwise suppressed limbs.'' However, I prefer to follow convention by using the term ''sternum'' to indicate that portion of sclerotization one sees in the checkered beetle adult abdominal segment. The figures of the reproductive organs show one of two ovaries, one of two testes, and one of two pairs of male accessory glands. The short transverse lines in the Character-Matrix Table (table 1) denote that a particular character state was not observed in a species group.
The excellent work of Rolland W. Brown (1966) was very helpful in the selection of specific epithets. The locality label information associated with each holotype specimen is presented in the species descriptions sequentially and precisely in the form that such information is written on the pinned specimen labels that are attached on the holotype specimen. In the ''Paratypes'' section of each new species description I have followed a sequence of recording locality information as follows: Country: State, Province, or Department: Specific locality. When more than one field collection was made from the same local locality, and the collections differ only in date, I separated the collection dates by a semicolon. Different localities within the same state, province, or departments were also separated by a semicolon. Different states, provinces, or departments, within the same country were separated by a colon. I examined the primary type of all nominal species included in this study.
The members of Aphelocerus and all New World genera with a well-developed basal denticle on the tarsal claws, such as Caestron, Placopterus, and Enoclerus, have a particularly long seta near the apex of the elytra. I have ascertained that this is a synapomorphic characteristic that links the aforementioned genera evolutionarily. I have named this extraordinarily long seta a ''trich' '. As no bothrium was noted at the base of this seta, it cannot be termed a trichobothrium. NO. 293 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY

ASSESSMENT OF SPECIES-LEVEL DISCONTINUITIES
The species concept applied in this contribution is based on fundamentals established by Ernst Mayr (1969). As behavioral or other biologic evidence of reproductive isolation was unavailable, I relied on anatomical differences and geographic parameters to infer species status. In the absence of evidence to the contrary, specimens from allopatric populations with similar genitalic characteristics were considered conspecific. Conversely, beetles from sympatric populations with varying genitalic characteristics were considered separate species. I found the presence or absence and distribution of secondary degree (2Њ) elytral setae valuable for predicting conspecificity or nonconspecificity in conjunction with variations of genitalia characteristics. Secondary degree setae are shorter and more decumbent than primary setae (see fig. 260). The secondary setae are organized into a midelytral tuft in most of the species. The shape of the tuft, whether it is comprised of one or two variously developed setal patches, and orientation of the setae in each patch are also useful for discriminating species. The setal tuft must be viewed at different angles (by tilting the specimen) to allow light re-flections to bring out the true shape of the setal patches and the orientation of the setae in each patch. In some species the two, or three, setal patches are contiguous and as such may be interpreted as forming a single patch. However, in these cases, the direction of the setae in each patch will differ to establish whether a tuft is comprised of one, two, or three patches. Many species of the yungas species group are superficially similar such that preparation of the diagnostic key was very difficult. Interspecific differences of phylogenetic use were particularly scarce. Inconvenient characteristics, such as body size, had to be used on occasion to complete a diagnostic couplet. To facilitate the process of identifying species more, I provide illustrations of the elytral discal setal tuft of several species (for example, see figs. 165-183). The 66 nominal species presented in this work represent my assessment of the magnitude of anatomic and geographic divergence that represents reproductive isolation in the genus Aphelocerus. In my systematic projects with checkered beetles, I have found it necessary to examine type specimens that date to the 1800s. At times, there was doubt as to the authenticity of a specimen being the primary type, mainly due to discrepancies between pinned label information and information in published descriptions. Therefore, at the beginning of each species description I document the exact sequence of labels on the holotype or lectotype.

PHYLOGENETIC METHODS
The phylogenetic hypotheses presented herein are based on principles advocated by Willi Hennig (1966). Elsewhere, I have discussed these principles in detail (Ekis, 1977: 116;Opitz, 2004: 9). Character states were assessed as apomorphic or plesiomorphic on the basis of out-group comparisons, and the data matrix was analyzed with Hennig 86 version 1.5 (Farris, 1988).

REPOSITORIES OF SPECIMENS
The following abbreviations indicate collections from which specimens were borrowed, and were taken from Arnett, et al. (1993). My sincere thanks to the curators of these collections acknowledged in parentheses. AMNH

MIMETIC ASSOCIATIONS
Any naturalist who has collected beetles extensively in the Neotropics will attest to the abundance of resemblances of color patterns and/or body shapes across familial lines. Such similarities among phylogenetically ''unrelated'' species are difficult to interpret as chance occurrences. They are often very fine tuned phenotypic similarities and invite the speculation that they represent some kind of adaptive convergence. The concept of mimicry, although not easily proven, is often a logical explanation for such convergences among distantly related species. However, as acknowledged by Hespenheide (1995: 146), ''most cases of mimicry cannot be subjected to experimental verification because of the rarity of the putative mimics and the difficulty in designing an experimental protocol that would realistically test a given case' '. . . of mimicry. Integumental color, patterns of white setae on various parts of the integument, and body facies strongly suggest that species of Aphelocerus are involved in a mimetic complex. I do not believe that the basis of this mimicry is distastefulness, but rather that it is based on such factors as escape behavior or morphological resemblance to aggressive models such as ants. It is my contention that Aphelocerus species are involved in a mimetic complex, probably Mullerian, that includes species of Buprestidae, Cerambycidae, Chrysomelidae, Curculionidae, Formicidae, and spiders.
I observed live A. myrmecoides, n.sp., among Myrmex weevils moving on broadleaf herbaceous hedge growth. The similarity between these particular clerids and the weevils is very profound in general form (compare figs. 163, 164) and in such anatomical details as the presence of white setal tufts on the sides of the body. Their locomotory differences, however, betray their identity with the clerid having a rapid scurrying movement and the weevil a slow, more deliberate gait. At present, one can only speculate about the functional basis of this suspected Mullerian complex. However, the extraordinary development of the antenna and legs among some of these beetles suggests a Batesian mimicry involving ants or perhaps spiders.
Members of the myrmecoides species group have an oval, short hind body and highly convex elytra that could reflect an adaptation towards the cephalothorax and abdomen body plan of a spider. The locomotory behavior of jumping spiders (Salticidae), which often share a leafy habitat with these clerids, could serve as the selection factor towards an antipredatory mechanism evolved by a variety of photophilic beetles. NO. 293 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY I (Opitz, 2004: 13) observed ''jumping'' behavior among plocamoceran clerids and suggested that such behavior was associated with fly-escape behavior as described by Hespenheide (1973: 52) for species of Epiphloeus Spinola. One may also speculate that this mimetic complex, which includes Aphelocerus, involves a mimetic relationship in which the similar color, smooth body, and very similar habitus of various species of beetles and spi-ders may possibly be intertwined in a Mullerian association. Hespenheide (1973: 52) describes a similar mimetic complex in which beetles imitate the reddish forebody coloration and quick flight escape behavior of tachinid fly models. Moreover, Poinar (1999: 10) suggests that beetles with smooth bodies, characteristic of some of the above mentioned aphelocerans, are often characteristic of leaf beetles that escape predation by ants in that the beetles are difficult to grasp because of the smooth contour of their bodies. Lastly, Hespenheide (1987: 53) commented on the color and habitus similarity between the zygopine weevil genus Lissoderes and the otidocephaline weevil genera Myrmex and Ooterinus, and he noted that species of Aphelocerus belong to this black, strongly shining assemblage of beetles.

FLORAL ASSOCIATIONS
Although checkered beetles are thought to be predominantly predaceous on lignicolous insects, they frequently occur within flowers. Checkered beetle anthophily has been reported by Foster (1976: 64), Mayer (1976: 2), Crowson (1964: 303), Hawkeswood (1981Hawkeswood ( : 125, 1982, and Opitz (2002: 241). To my knowledge there are no published reports of anthophily among the species of Aphelocerus. However, information from specimen labels suggests that the members of several Aphelocerus species do frequent blossoms, although their role in such a niche is unknown. According to information from specimen labels, anthophily among apheloceran species has been reported by James E. Wappes (A. leucomelas [Chevrolat] specimens feeding on blossoms of a woody plant), Jose A. Clavijo (A. sturnus Kirsch beetles within blossoms of Inga marginata), Frank T. Hovore (A. cohibilis, n.sp., individuals from a flowering tree species of Croton), and Frode Ødegaard (A. catie, n.sp., beetles on Guatteria dumetorum, Jacaranda copala, Nectandra purpurascens, and Inga cocleensis, and A. myrmecoides, n. sp.,

in flowers of Forsteronia myriantha).
Because apheloceran specimens have been captured on a variety of flower blossoms, one might presume that they feed on pollen. However, the construction of their mouthparts and development of the digestive system suggest that the flower visiting aphelocerans are predators of flower-visiting insects or soft-bodied arthropods. However, Frode Ødegaard reports (personal commun.) that specimens of A. catie, n.sp., did not feed on small anthophilic arthropods when the clerids and other small arthropods were placed together in small vials. Therefore, the possibility that these clerids feed on pollen and nectar cannot be discounted as both of these flower products serve to nourish other checkered beetles of the subfamily Clerinae (Opitz, 2002). Moreover, Ødegaard observed abundant specimens of A. catie, n.sp., scurying among inflorecenses of Inga cocleensis, which is very reminiscent of the flower foraging behavior of Eleale aspera Newman (Opitz, 2002: 243).
Indeed, within the Cleridae there seems to be a positive correlation between an abundance of integumental pubescence and an anthophilic life style. For example, members of the Holarctic genus Trichodes (Foster, 1976: 65), Chilean Calendyma (Crowson, 1964: 303), and Australian Eleale and allies (Hawkeswood, 1982: 31;Opitz, 2002: 241) are among the outstanding examples of the degree of pubescence-anthophilic life style correlation. The functionality of the correlation, of course, is that a densely setose integument, particularly on the insects' dorsum, would facilitate a pollen harvest, much like the densely setose pollen baskets facilitate pollen collection of the honeybee.
Further, in Aphelocerus there exists an interesting transformation of elytral pubescence in the development of the elytral middiscal setal tuft. Also, there seems to be a gradual reduction of the dense elytral pubescence from members of the more primitive leucomelas species group towards the less and less pubescent condition in the more advanced scutellaris-myrmecoides-formicoides line of species groups. Members of the batesi species group (for example, A. catie, n.sp.) and ciliaris species group (for example, A. ciliaris, n.sp.), which have highly setose elytra, have been reported on blossoms (Rifkind, personal commun.). Conversely, members of the more derived scutellaris-myrmecoides-formicoides line have an increasingly glabrous elytral disc ( fig. 164). The latter species groups are clearly involved in mimetic life styles. In some of these mimetic species, such as A. formicoides, n.sp., where the body dorsum is relatively glabrous, elytral pubescence would detract from the deception to look like a more glabrous cuticular body model such as found in an ant. Conversely, members of A. eriodes, n.sp., with their clearly arachnoid body form, are densely setose on the dorsum, suggesting the trichose dorsum of a spider model. I have often wondered whether an investigation into the relationship between the intricacies of integumental pubescence and form of life style might not lead to significant evolutionary hypotheses within Cleridae.

FIELD OBSERVATIONS
During an expedition to Los Altos de Panama, January 2, 2002, the last day of fieldwork, Lee Herman and I decided to make one more attempt to obtain specimens of apheloceran species known to occur on Cerro Campana ( fig. 1d), and possibly obtain biological information about them. This was my third attempt to learn something about the biology of the apheloceran species known to occur in the Cerro Campana highlands (fig. 1d). I had worked the mountain several times before but was unsuccessful at observing apheloceran life habits, or determining the whereabouts of their immature stages. About one hour before the fieldwork was to end, I found what had eluded me for quite some time, checkered beetles flying into a recently felled tree trunk with a particularly strong fragrance emitted from exposed cuttings of wood and leaves.
According to Orlando Nuñes, an indigenous Panamanian living in the area, this particular tree had been down for seven days. Among the checkered beetles that this tree attracted were 12 specimens of Enoclerus insidiosus (Gorham), eight of another Enoclerus sp., two specimens of Ichnea, one of Madoniella erythrocephalus (Gorham), and most relevant to this study, two specimens of A. myrmecoides, n.sp., scurrying among some 11 specimens of Myrmex weevils. The tree in question did not show any evidence of flowers. In addition to these beetles, I observed and then collected two specimens of bostrichids that were in the process of boring into a debarked portion of the aforementioned tree trunk. It was an exciting moment to finally observe some evidence suggesting that aphelocerans are attracted, as are many other checkered beetles, to tree volatiles and at least potentially seem involved in predatory activity associated with lignicolous insects. As A. myrmecoides, n.sp., has also been observed to frequent blossoms of Forsteronia myriantha (loc. cit.) it seems likely that at least some members of Aphelocerus are omnivorous since they may consume nectar and pollen from blossoms and prey on lignicolous insects when blossoms are not available; perhaps their diet comprises both plant and animal matter.
An interesting sidebar to the most recent field experience on Cerro Campana, Panama, was a legendary story by Orlando Nuñes about the felled tree on which I found many clerids. It seems that the indigenous peoples of Panama, possibly members of the tribe Gnobe Bugle or '' Guaymies'', made use of this species of tall tree as observation towers, and when a Spaniard asked a native about the name of this tree, the native replied in broken Spanish ''espaber'', literally meaning ''I climb to see''. Thus evolved the legendary vernacular name of this tree which ended a last hour of fieldwork on a culturally rich and scientifically rewarding note.
During three excursions to the charming village of Volcan, nested in a volcanic crater (1344 m) and surrounded by the highlands of Chiriqui, in Panama, I encountered many specimens of Aphelocerus chiriqui, n.sp., in two particular habitats. The first involved a natural reserve known as Hacienda Las Lagunas del Volcan, whose primary lakeside forests have trailside vegetation laden with woody shrubs densely intermixed with herbaceous vines ( fig. 1c). Numerous A. chiriqui adults were taken at this site during May and August by beating. It was puzzling at first to realize that very few of these clerids could be seen scurrying on the surface of the broad vine leaves. Yet, beating this assemblage of vegetation consistently yielded specimens. Eventually, I realized that these clerids, along with a variety of other beetle predators, were foraging primarily on the underside of the leaves (as seen in fig. 1a) and along the stems of the herbaceous vines, possibly consuming immature/adult homopterans such as membracids, or feeding on the eggs of the multitude of chrysomelids ovipositing on the underside of leaves.
The second, ''hot spot'' for aphelocerans and other clerids (in the aforementioned highlands) was located on the northeastern slopes of a Chiriqui mountain (about 6 km north of Volcan, at about 1500 m) within an escarpment through which daily gusts of wind sweep towards and up the mountain slopes. Specimens were collected along a narrow, roughly paved winding road with overhanging herbaceous plant assemblages. Beneath the overhanging verdure one would, almost invariably, find patches of flowering Impatiens, whose presence served as indicator plant species for the potential collecting of checkered beetles. Apheloceran checkered beetles, like impatience plants, are found most often on sun-intensive moist slopes. After several days of fieldwork it became obvious that this particular portion of the mountain escarpment, with its wind thrusts, swept a variety of insects, including taxonomically diverse species of clerids, onto the slopes of the mountain, especially during midmorning periods of intensive sunlight (usually about 10:00 a.m.). Collecting efforts were poor along the same mountain road (leading to Rio Sereno from Volcan) on slopes that were shaded and where wind gusts were minimal or absent.
Most recently, during May 2002, Lee Herman and I spent a week collecting in Selva Negra, a private preserve of virgin cloud forest in the western highlands of Nicaragua. The Kühl family, a gracious people of German ancestry, is profoundly dedicated to the preservation of the Nicaraguan jungle habitats. Selva Negra (''Schwarzwald''), essentially a community of Nicaraguan citizens, maintain the mountain resort with a management style that emphasizes organically grown products within an uncompromising conservation framework.
Along the ''Cody'' trail, which is proximal to a large pond and adjacent to a narrow extension of a coffee grove that eventually coalesces with a dense virgin cloud forest known as ''Monkey Territory'', I experienced outstanding results in the collection of generically diverse checkered beetles. Among the catch, there were two new species of Aphelocerus (A. cirritus, n.sp., and A. capillus, n.sp.) that were collected by beating overhanging tree branches, along the trail, intertwined with wild grape and other vines. Some of the nonliving vegetation, such as hardwood branches, was particularly rich in Cerambycidae.

NATURAL HISTORY INFORMATION FROM SPECIMEN LABLES
Many of the specimens on which this treatise is based were collected by beating tree foliage, particularly oak trees in tropical forests. Label data suggest that aphelocerans may be collected on foliage or woody branches of the following plants: Nectandra purpurascens, Calophyllum longifolium, Inga cocleensis, Maranthes panamense, Lysiloma divaricata, Spondias mombin, Brosimum alicastrum, B. utile, Inga marginata, Forsteronia myriantha, Coumarouna oleifera, and species of Piper, Acasia, Quercus, Croton, and Arum (an epiphytic vine).
Although specimens were collected throughout the year, most were captured from May through July, at elevations ranging from 97 m to 3000 m, most collected between 1500 and 2000 m. The ''beatingsheet'' method of collecting seems to be the most productive manner of obtaining these insects, although some specimens were also collected with sweep nets, light traps, and Malaise traps.

DIAGNOSIS OF APHELOCERUS
One of the most interesting, but difficult to find, generic characteristic of these beetles is the presence of an elytral trich, an extraordinarily elongated seta near the apex of each elytron ( fig. 257). Superficially, however, most of these beetles are conveniently recognized by their shiny black integument and the presence of a streak of silvery setae at the base of the sutural margin and/or on the elytral disc. Only in specimens of A. coalitus, n.sp., A. delicatulus Barr, A. affaniatis, n.sp., and sometimes in specimens of A. inconstans Gorham, is the dorsum partially rufous or variously testaceous. Specimens of Aphelocerus have the pronotum consistently narrower than the width of the elytra across the humeri. Further, the members of most of the species show a tuft of silvery setae at the middle of the elytral disc that is usually divided into two variously developed setal patches (anterior patch and posterior patch) that in aggregate are usually proximal to the sutural margin (see frontispiece).
The integumental pubescense, particularly those found on the frons, pronotum, and el-ytra, are identified as primary (1Њ) or secondary (2Њ) setae. The primary setae (fig. 260) are usually more robust, more vertical, and not aggregated into groups whereas the secondary setae (fig. 258) are slender, shorter, more decumbent, and arranged into one, two, or three patches that combine to give the appearance of a single setal tuft.
The assignment of specimens to species is very difficult. Variations in aedeagal characteristics provide the most reliable criteria for species-level identifications. One particularly dramatic exception to interspecific aedeagal diversity is the virtually identical shape of the aedeagus in males of A. echinatus, n.sp. (fig. 144b), and A. affaniatis, n.sp. (fig. 144a). What makes this aedeagal similarity extraordinary is the extent to which the members of these species differ externally.
For identification of specimens of Aphelocerus to species level, the aedeagus of all available males should be examined. Other attributes used to discriminate the species are length of the antenna and the shape of its club, presence or absence of white setal tufts on the frons and lower side margins of the pronotum, size and shape and number of setal patches of the elytral middiscal setal tuft and the direction of their seta, pronotal shape, width of the pronotum in relation to the width of the elytra across the humeri, degree of angularity of the epipleural margin in the posterior fourth of the elytra, convexity of the posterior half of the elytra, length of the metatibia, and shape of the pygidium and sixth visible abdominal sternum. Apheloceran specimens from whom elytral discal setae have been abraded may be difficult to identify, but the minute punctations from which the tuft setae arise give an indication of the presence and shape of the tuft. In a few cases geographic distribution was used as a convenient characteristic to assign externally similar specimens to species. Aphelocerus Kirsch, 1870: 369. Type species: Aphelocerus sturnus Kirsch, 1870: 370. By monotypy. Lohde, 1900: 23. Schenkling, 1903: 5, 24, 1910: 26. Blackwelder, 1945: 382. Corporaal, 1950: 56. Winkler, 1961: 39. Barr, 1976: 18. Rifkind, 1995: 17. Adelphoclerus Wolcott, 1910: 356, 1927: 73. Type species: Adelphoclerus nitidus Wolcott, 1910 357 (junior synonym) . Corporaal, 1942. Corporaal, : 137, 1950 Size: Length 3.2-8.6 mm; width 1.5-4.0 mm. Form (see frontispiece): Oblong; robust, commonly three times longer than broad; elytra plane in basal two-thirds and deflexed in apical third; members of the formicoides, scutellaris, and myrmecoides species groups variously convex in pronotal and elytral form; in some of these species groups the abdomen is proportionally shortened. Integument: Shiny black, rarely basal half of elytra reddish; cranium, pronotum, pterothorax, abdomen, legs sometimes cyanescent; elytra and legs rarely testaceous; cranium, pronotum, and elytra rarely castaneous. Vestiture: Integument densely setose; dense patch or patches of white setae (herein designated as ''tufts'') may be present on frons ( Rica), and Chiriqui (Panama) each possess a number of cryptic species.

SPECIES GROUPS OF APHELOCERUS
The species of Aphelocerus can be separated into 15 species groups based on the presence or absence of elytral asetiferous punctations ( fig. 259), distribution of secondary elytral setae ( fig. 260), texture of the elytral surface, development of the elytral middiscal setal tuft, extent of development of the genae and epicranium, pronotal microsculpture, microsculpture at the base of the elytra, length of the pronotum, macrosculpture on the pronotal disc, presence of the frontal setal tuft, prominence of the legs, degree of elytral convexity, and shape of the parameres.

coalitus group
The members of this species group are relatively large clerids (6.0-10.0 mm) whose pubescent pattern does not conform to the typical pattern as seen in the fronticepiece. In these beetles, there is an admixture of dark and pale setae on the elytral disc. The pale setae may or may not be organized in narrow lines or oblique patches. The presence of asetiferous punctations, particularly prominent in the posthumeral regions, is an apomorphic characteristic for this group of species. Further, the secondary elytral setae are not concentrated into transverse tufts at the middle of the elytra. The combined known range of this species group extends from the Oaxacan highlands of Mexico to the lower elevations of central Costa Rica. echinatus group The subapex of the parameres have an acute spine ( fig. 125). The two species that comprise this species group inhabit southern Mexico, one from the Chiapan highlands, and one from the Yucatan Penninsula.

ciliaris group
The decumbent, 2Њ elytral setae begin to change direction at the middle of the elytral disc, obliquely directed towards the epipleural margin. Anterior to this ''incipient'' setal aggregation, the 2Њ setae are directed towards the front; towards the back behind the aggre-gate. The members of this species group have been found only in southern Mexico.

bispineus group
This species group is comprised of four species whose male members show a very unique development of the posterior margins of the parameres. The parameres are predominantly truncate except at their most mesal margin where they narrowly flare out to form a small papillose protrusion (fig. 193). As in the members of the ciliaris species group in some of the specimens of the bispineus group, particularly those of A. acuticolis, n.sp., and A. bispineus, n.sp., the middiscal setal aggregate (fig. 235) suggests an evolutionary transition towards a distinct, elytral middiscal setal tuft as seen in the frontispiece. The members of this species group are known only from southern Mexico.
acanthus group These beetles are characterized by the extensive development of the elytral middiscal setal tuft. The setal tuft reaches its highest development in the members of this group; it extends from the sutural margin to the epipleural margin ( fig. 38). Collectively, the members of this group have a distribution that ranges from southern Mexico to Argentina.
sculptilus group These small sized aphelocerans are easily distinguished from members of the other species groups by the fine microsculpture on the pronotal disc that is synapomorphic for the group. The range of this group extends from the western slopes of Costa Rica to the Chiriqui highlands of Panama.
irroratus group This is a monotypic group whose member has a gritty microsculpture on the base of the elytral disc anterior to the elytral middiscal setal tuft ( fig. 34). Also, the elytral epipleural and humeral margins are densely vested with short white setae. Specimens have been collected from Chiapas, Mexico, to the western highlands of Guatemala.
immarginatus group This monotypic species group involves specimens whose humeral umbo is very prominent, the elytra are conspicuously depressed behind the umbo with the middiscal setal tuft set in the depression, and the posterior two-thirds of the elytral disc is strongly convex ( fig. 40). A. immarginatus (Chevrolat) specimens are known only from the highlands of Colombia.

yungas group
The members of this group of species show a development of elytral middiscal setal tuft that is transitory towards its highest development as seen in specimens of the acanthus species group. The tuft is comprised of two patches of white 2Њ setae. In most cases the setae of the anterior patch are directed anteriorly while those of the posterior patch are directed laterally or posterolaterally ( fig. 182). The geographic range of this species group extends from Mexico to Bolivia.
batesi group This is the most speciose group in the genus. In the members of this group the posterior patch is reduced to a few setae or is absent. When the posterior patch is absent, the setae of the anterior patch are all pointing in the same direction. In aggregate, the range of this species group extends from Mexico to Ecuador.

panus group
The campaniform pronotum and conspicuously slender antennae are apomorphic characteristics of the members of this species group. Their geographic range extends from Costa Rica to Brazil. formicoides group This group is comprised of two species whose members more than any other aphelocerans have the appearance of ants. Their pronotum proper is particularly globose, the elytra are short and very convex ( fig. 45), and as in the case of the members of the cheliferous and myrmecoides groups, the elytral disc is faintly carinate longitudinally. NO The species range from southern Mexico to western Panama.

cheliferous group
These stout-bodied beetles have longitudinal ridges on the elytral disc. The testaceous color of the antennal apex is particularly notable in these beetles. They are dis-tributed from southeastern Mexico to eastern Guatemala.

scutellaris group
In specimens of this group of species the posterior region of the pronotal disc is transversely wrinkled and the parameres are distinctly digitiform. The latter characteristic is   also present in the myrmecoides species group. These beetles are particularly robust, having a size range from about 5.0 to 8.0 mm. Geographically these beetles range in distribution from southeastern Mexico to Brazil. myrmecoides group Specimens of this species group have an abdomen that is proportionally very short. They share some characteristics with those of the formicoides and cheliferous group; for example, the elytral disc shows very shallow longitudinal swellings, the elytra are devoid of setal tufts and are exceptionally polished, and the legs are conspicuously lengthened with the femur extended well beyond the elytral apex. The pronotal tuft (on the lower sides of the pronotum) is highly developed in these beetles. Their geographic range extends from Costa Rica to Ecuador.

TROUBLESOME COUPLETS IN KEY TO SPECIES
Couplet 6(2): In this couplet it is imperative to distinguish between a midelytral setal tuft as pictured in the frontispiece and a ''loose'' rectangulate aggregate of pale setae as pictured in figure 235. Couplet 30(28Ј): The bluish luster on the pronotum varies somewhat in intensity. It is best to view the pronotum slightly tilted to the front.
Couplet 38: A middiscal setal tuft is defined as having two patches when at least some of the posterior setae of the tuft are oriented towards the back.

DESCRIPTION OF APHELOCERUS SPECIES
COALITUS GROUP Aphelocerus leucomelas (Chevrolat) Figures 29,30,54,126,127,190,255,257,259 Gorham, 1882: 162. Corporaal, 19421950: 147. DIAGNOSIS: These beetles are easily distinguished from other aphelocerans of the coal-itus species group by their large size (about 10 mm) and by the often present short, longitudinal and obliquely arranged streaks of white setae on the elytral disc (figs. 29, 30). A. leucomelas (Chevrolat) specimens without white elytral setal streaks may be distinguished from superficially similar specimens of A. coalitus, n.sp. by the absence of decumbent white setae in individuals of A. leucomelas (Chevrolat) which are densely distributed throughout the elytral disc in specimens of A. coalitus, n.sp. DESCRIPTION: Size: Length 8.9-10.1 mm; width 3.1-4.2 mm. Integument: Black, with streaks of white setae on elytral disc. Vestiture: With tuft of white setae on lower sides of pronotum, metepisternum, and elytral suture; cranium sparsely setose; pronotum densely vested with proclinate setae; mesoscutum and mesoscutellum densely matted with white setae; midelytron usually vested with five, variously developed, obliquely arranged streaks of white setae, setal streaks increase in length from those near suture to those near epipleuron, streak near epipleuron very long; elytral disc also vested with stout verical and short reclinate black setae; dense vestiture of setae on pterothorax, abdomen, and legs predominantly white. Head: Width across eyes equal to width across greatest width of pronotum; finely sparsely punctate; interocular depressions particularly deep; frontal umbo prominent; eyes oblong, moderately convex; antenna as in figure 54. Thorax: Pronotum elongate (47:51), narrower than width of elytra across humeri (47:63), densely finely punctate, side margins moderately arcuate, subapical depression very shallow; elytra with asetiferous and setiferous punctations and moderately convex in posterior half, depth of humerus 24, greatest depth in posterior half 30, humerus projecting. Abdomen: Male pygidium somewhat trigonal (as in fig. 101 VARIATIONS: The antennal club is less robust in specimens from Costa Rica, the elytra are nearly brunneus in one specimen from Comayagua, Honduras, and the definition and number of white setal streaks on the elytral disc vary. The streaks are absent in some specimens from Guatemala, Honduras, and all available specimens from Costa Rica. The specimen from El Progreso, collected by J. E. Wappes, differed in that the lower sides of the pronotum lack a definitive white setal tuft. For the present, I ascribe this difference to represent intraspecific variation. NATURAL HISTORY: From Mexico, specimens were collected during May, June, and July; from Guatemala during June and July (690-762 m); from Honduras during May and June, (609-850 m); and from Costa Rica during April, May, and June (70-600 m). J. Rifkind and P. Gum  REMARKS: There are several seemingly disjunct populations of this species ranging from southeastern Mexico to Guatemala, Honduras, and Costa Rica. The specimens from Costa Rica do not have white 2Њ setae on the elytral disc, a setal development also found on one specimen from Guatemala. All of the other northern specimens examined have longitudinal 2Њ setal streaks, albeit variable in size and form. The aedeagus is virtually identical in all males examined. The homogeneity of male genitalia and the variation of the 2Њ setal streaks in the northern specimens suggest that the somewhat disjunct populations of this species are conspecific.  Est. Biol. Chamela, 2-VII-1995, R. L. Westcott (WOPC, 1); vic. Est. UNAM, 9-19-VII-1993, J. Heuther (JPHC, 1; JEWC, 1; WOPC, 1); Mexico, Playa Teopa, 6-VII-1991, beating vines (JNRC, 1); ''Mexico'': Lange (MNHN, 1).

Aphelocerus coalitus, new species
DIAGNOSIS: The dense vestiture of white decumbent 2Њ setae on the pronotum and elytra of these beetles will easily distinguish them from A. leucomelas  with dense aggregate of white setae on pronotal lower sides, metepisternum, and elytral suture; mesoscutellum matted with white setae; elytral disc densely vested with short white decumbent setae that are proclinate in anterior half, reclinate in posterior half, and sometimes arranged into distally confluent longitudinal rows; posterior half of epipleuron densely lined with band of white setae. Head: Width across eyes slightly narrower than width across widest part of pronotum (48:53); finely punctated; interocular depressions and frontal umbo shallow; eyes oblong, convex; antenna as in figure 55. Thorax: Pronotum elongate (53:60), slightly narrower than width of elytra across humeri (53:63), coarsely punctate, tendency towards scabrous, side margins feebly arcuate, subapical depression faintly visible; elytra with asetiferous punctations, elytra feebly convex in posterior half, depth at humerus 35, greatest depth in posterior half 40, surface scabrous. VARIATION: The elytra may be subcarinate and may reflect a brunneus cast. In some specimens the humerus is testaceous and the . Aphelocerus extensivus,dorsal. 38. A. patulus, dorsal. 39-40. A. immarginatus (39, dorsal; 40, lateral). linear arrangement of white setae on the elytal disc is not clearly defined.
NATURAL HISTORY: Specimens were captured during June and July. One specimen was taken in a tropical deciduous forest, at light. DISTRIBUTION (map 4): The distribution of this species seems to be restricted to Mexico, along the western slopes of the Sierra Madre Occidental and the more southern Sierra Madre del Sur.
ETYMOLOGY: The trivial name coalitus is derived from the Latin adjective coalesco (unite). I refer to the posterior coalescence of the white setal lines near the elytral apex that is clearly visible in some specimens.
VARIATION: The femora and tibiae may be testaceous; the elytra vary from slightly violaceous to piceous.
NATURAL HISTORY: The available specimens were collected from Mexico during June (UV light at 800 m) and July (1006 m), and from Guatemala during early June at 950 m.
DISTRIBUTION (map 21): Known from southeastern Mexico and southwestern Guatemala.
ETYMOLOGY: From the Latin adjective echinatus (spiny). I refer to the spine on the parameres. DIAGNOSIS: The reddish coloration on the basal half of the elytra will distinguish the members of this species from the closely related members of A. echinatus, n. sp. which differ by having the elytra totally blue-black.
VARIATION: The dark posterior portions of the elytral disc vary in intensity. The head and prothorax of the male from Yucatan is dark brown.
NATURAL HISTORY: Specimens were collected in May and June.
DISTRIBUTION (map 4b): Specimens have been collected from the Yucatan Peninsula.
ETYMOLOGY: The trivial name affaniatis is a Latin compound name derived from the adjectival affania (ϭ chatter) and the suffix -tis (ϭ action). The name refers to the frequent occasions during which I have discussed with colleagues the generic placement of this and other species akin to this species. DIAGNOSIS: The dense vestiture of short white setae on the dorsum gives these beetles a silky appearance, especially on the elytral disc where the setae are directed posteriorly on the elytral posterior half and anteriorly and posteriorly on the elytral anterior half. The elytral surface is shallowly rugose. At midelytron, there is a narrow admixture of reclinate, proclinate, and laterally projecting setae that anteriorly interphase with mostly proclinate setae. Immediately behind the midelytron the predominance of white reclinate setae is interupted by a centrally located diffuse patch of black setae ( fig. 25). A middiscal elytral aggregate of white setae is not present. Specimens of the other species in this species group, A. citimus, n.sp., have only a few pale setae on the anterior half of the elytral disc.

CILIARIS GROUP
DESCRIPTION: Size: Length 4.8-5.5 mm, width 1.8-2.1 mm. Integument: Piceous, with or without cyanescent hue. Vestiture: Clypeus, frons, and epicranium vested with long subrecumbent white setae; setae proclinate on clypeus and lower sides of frons, directed laterally on interocular depression, and mesally on upper frons, frontal umbo, and epicranium; pronotum densely vested with long subrecumbent proclinate white setae intermixed with longer, more erect, black setae, setae on pronotal side margin conspicuously longer than discal setae; mesoscutellum matted with white setae; elytra vested with short white setae that are proclinate at elytral anterior half, setae oriented laterally at elytral middle and posteriorly in elytral posterior half; elytral sutural margin densely setose, but not producing a setal tuft; metepisternal tuft moderately prominent; antenna, pterothorax, legs, and abdomen densely setose. Head: Width across eyes slightly narrower than width across pronotum (28:29), coarsely punctated; interocular depressions and frontal umbo broad and shallow; eyes subspherical, moderately convex; antennae short, much shorter than length of pronotum, as in figure 48. Thorax: Pronotum feebly transverse (29:28), narrower than width of elytra across humeri (29:36), profusely finely punctated, side margins moderately arcuate, feebly incised by anterior transverse depression; elytra feebly convex in posterior half, depth at humerus 15, greatest depth in posterior half 20; surface arenose to feebly scabrous. VARIATIONS: The legs and elytral colora-tion vary from brunneus to cyanscent and in specimens from the southern portions of the distribution the apical region of the elytra is vested with more dark setae than light setae. NATURAL HISTORY: Specimens have been collected from April through August. One specimen from Chamela is associated with Lysiloma divaricata. Two specimens were collected by beating deciduous trees at 243 m. Two other specimens were taken at 579 m and four at 1228 m. Several beetles were collected at light. Rifkind and Gum captured one specimen by beating Acacia at 396 m.
DISTRIBUTION (map 1): This species ranges from the western slopes of the Sierra Madre Occidental to western forests of the Transvolcanic Sierra to the more southern Chiapan highlands of the Sierra Madre of Mexico.
ETYMOLOGY: The trivial name ciliaris is derived from the Latin noun cilium (eyelid) and the suffix -is (having the nature of). I refer to the abundance of fine setae on the dorsum of the elytra. (Specimen point mounted, sex label affixed to paper point, white, hand printed; support card, white, locality label, white, machine printed; LACM repository label, white, machine printed; holotype label, red, machine printed; plastic vial with abdomen and aedeagus.) PARATYPES: None. DIAGNOSIS: The available specimen superficially resembles the member of A. inconstans (Gorham), but in citimus beetles the lower aspects of the pronotum lack the dense aggregate of the white setae.
VARIATIONS: Not studied.
NATURAL HISTORY: The holotype specimen was captured during October.
DISTRIBUTION: Known only from Southern highlands of Chiapas, in Mexico.
ETYMOLOGY: The epithet is a Latin adjective that refers to the metallic blue-green color of this beetle. Figures 52,194,195,255a; map 21 HOLOTYPE: Male. Mexico: Chiapas, Bochil, 10 km S., X. 1. 1989, R. L. Penrose (CASC). (Specimen point mounted, sex label affixed to paper point, white, hand printed; support card; locality label, white, machine printed; holotype label, red, machine and hand printed; plastic vial with abdomen and aedeagus.)
DIAGNOSIS: Among the species that have a parameral accumination this species may be identified by the presence of a dense aggregate of pale setae on the lower sides of the pronotum. This characteristic also separates A. bispineus, n.sp., beetles from superficial similar Chiapan members of A. ciliaris, n.sp. DESCRIPTION: Size: 3.5-5.0 mm; width 1.6-2.1 mm. Integument: Black, with violaceous tinge; pronotal lower sides vested with dense aggregate of pale setae; sutural tuft very reduced; midelytron with loose aggregate of setae whose orientation is towards epipleural margin. Head: Width across eyes equal to width across pronotum (30:30); cranium finely puctate; interocular depressions and frontal umbo shallow, eyes subspherical, moderately convex; antenna as in figure 52, as long as length of pronotum. Thorax: Pronotum as long as wide (30:30), considerably narrower than width of elytron across humeri (30:40), finely punctate, subapical depression faintly indicated, side margins moderately arcuate; elytra plane, depth at humeris 15, greatest depth in posterior half 15, surface shallowly rugose. Abdomen: Pygidial posterior margin evenly arcuate; aedeagus as in figure 194; paramere with medial acumination; apical region of tegmen with paralateral bands of serrations; phallic plicae particularly broad (fig. 195 (Gorham) these beetle are distinguished by the more squat body form, more transverse pronotum, and by the more profuse distribution of setae on the sutural margin or the elytral. The extension of the middiscal elytral tuft to the epipleural margin will separate these beetles from those of A. coactus, n.sp.
VARIATION: Not studied. NATURAL HISTORY: The available specimen was collected during early June at 950 m.
DISTRIBUTION (map 27): Known only from the type locality.
ETYMOLOGY: The specific epithet is taken from the scientific name of the wooly mammoth. I refer to the stout body and the densely pubescent characteristics of these beetles.  183) is a broad patch of setae that extends from the sutural margin to the epipleural margin.
VARIATION: In some specimens the legs are testaceous.
DIAGNOSIS: These beetles may be distinguished from the superficially similar speci-mens of A. ciliaris, n.sp., by the dense mat of white hairs on the lower side of the pronotum. Also, in A. inconstans (Gorham) specimens, white setae are distributed in the apical half of the elytra ( fig. 26), not throughout the elytral surface, which is the case in most A. ciliaris, n.sp., specimens.
VARIATION: The known Costa Rican specimens of this species have the posterior patch of the elytral setal tuft reduced near the epipleural margin. Further, the parameres of the Costa Rican males are slightly shorter. I attribute this difference to geographical variation.
NATURAL HISTORY: Specimens were collected from May to September, at altitudes ranging from 762 to 1800 m.
DISTRIBUTION (map 21): The known distribution of this species extends from southern Costa Rica to the highlands of western Panama.

DIAGNOSIS:
The outer margins of the elytra are subparallel. This along with the small size of these beetles (4 mm) will distinguish these beetles from the other aphelocerans with the pronotal disc microsculptured. From superficially similar A. chondrus, n.sp., spec- NATURAL HISTORY: Specimens have been collected in January, March, June, and July; from 100 to 500 m in altitude. Two specimens were collected on Croton, another by beating foliage from a flowering tree.
DISTRIBUTION (map 27): Known only from central Costa Rica. ETYMOLOGY: The specific epithet cohibilis is a Latin adjectival that translates as terse. I refer to the abbreviated condition of the posterior patch of the elytral middiscal setal tuft.  A. coactus. 157. A. nitidus. machine printed; AMNH repository label, red, machine printed, holotype label, red, machine printed.)

IRRORATUS GROUP
PARATYPES: Twenty-seven specimens. Four from the same locality as the holotype (USNM, 1; JNRC, 1; WOPC, 2). Mexico: Chiapas: 6.4 km N Bochil, 4-V-1969 NATURAL HISTORY: In June, in Antigua, Guatemala, I collected four specimens at 2000 m by beating a stand of roadside hedgerow adjacent to an extensive pine forest. Other specimens were taken from June to August, by ''sweeping herbs in cleared fields'' and by ''beating dead leaves'', at altitudes ranging from 518 to 2439 m. DISTRIBUTION (map 9): This species ranges from the highlands of Chiapas, Mexico, to the southern extension of the Sierra Madre of Guatemala.
ETYMOLOGY: The specific epithet irroratus is a Latin adjective denoting ''covered with granules'' and it is used in reference to the granular condition on the surface of the basal third of the elytra.  COMBINATION. Chevrolat (1876: 14). Barr (1976: 18).
VARIATION: The specimens did not vary appreciably.

Aphelocerus cornuatus, new species
DIAGNOSIS: The combination of small size (4 mm), Mexican distribution, and presence of a bipartite elytral discal setal tuft ( fig. 167) will identify the members of this species. The acuminate-curvate shape of the parameres easily identifies the males. REMARKS: The locality label of the type specimen indicates that Atoyac is in ''Estado Veracruz''; however the only Atoyac locality known to me is located in ''Estado Guerrero''. Figures 67, 114 168) and there is a more pronounced swollen humeral umbo and deeper concavity behind the humerus.
VARIATION: The available specimens are quite homogeneous with the exception of the posterior patch of the elytral middiscal tuft with is slightly reduced in some specimens.
NATURAL HISTORY: The specimens were collected by beating overhanging trail vegetation rich in dead branches and broad leaf vines. Some were captured from a tangle of dense vines draped over short bushes.
DISTRIBUTION (map 10): Known only from the vicinity of the type locality.
ETYMOLOGY: The specific epithet is a Latin noun meaning ''hair''. I refer to the extensive development of the elytral middiscal setal tuft.
VARIATION: Except for the brunneus elytra on some specimens and slight differences in the conic form of the female pygidium, the members of this species do not vary appreciably.
NATURAL HISTORY: Specimens have been collected in April, May, June, July, August, and September; at altitudes ranging from 8 to 1148 m. In July, in a forest clearing in Tabasco, Mexico, at about 8 m in altitude, I observed and collected 43 specimens scurrying on foliage of Spondias mombin, a woody shrub known locally as ''Jobo''. J. Rifkind and P. Gum collected one specimen on flowers in a hardwood broadleaf forest.
DISTRIBUTION (map 5): The known range of this Central American species extends from southern Mexico and northern Honduras.
VARIATION: Except for the body size, these beetles did not vary appreciably.
NATURAL HISTORY: The El Salvador specimens were collected in June (500 m) and July.
DISTRIBUTION (map 10): From southern Guatemala to central El Salvador.
ETYMOLOGY: The specific epithet is a Latin adjective meaning ''stretch out''. I refer to the extended condition of the posterior patch of the elytral middiscal setal tuft.  figure 59. Thorax: Pronotum subequal in width and length (24:25); substantially narrower than width across humeri (24:32), finely punctate; side margins feebly arcuate, anterior transverse depression indistinct, elytra moderately convex in posterior half, depth at humerus 19, greatest depth in posterior half 25. Abdomen: Pygidia as in figure 107 and 108, female sixth visible abdominal sternum as in figure 109. Male genitalia: As in figure  131; aedeagus short.

BATESI GROUP
VARIATION: The posterior patch of the elytral middiscal setal tuft becomes progressively larger, more widened towards the epipleural margin, in specimens from southern Mexico, through Guatemala, and into Honduras.
NATURAL HISTORY: Specimens were collected during May, June, and July at altitudes ranging from 1219 to 2439 m. A Honduran specimen was captured in September.
DISTRIBUTION (map 8): Specimens have been found from the highlands of southern Mexico, central Guatemala, and eastern Honduras.
VARIATION: This is a highly variable species in such salient characteristics as integumental color (black to stramineous), development of midelytral setal tuft (sometimes faintly indicated or extended posteriorly into acute extensions; see figs. 33, 234, 237, 271), length of setal tuft on the sutural margin, degree of pygideal truncation, and in the ventral surface of the parameres (sometimes flanged or explanate in distal half [fig. 261] or with their outer margins slightly inflexed giving a subsaggitate appearance [ fig. 157]; the latter condition appears commonly VARIATION: In some specimens the elytra tend to be more brunneus than piceous (which may reflect a teneral condition of the specimens). The extent of development of the posterolateral outer angles of the parameres are variously expressed.
NATURAL HISTORY: No information available.
ETYMOLOGY: The trivial name is taken from the Latin feminine sagitta (arrow). I refer to the arrow-shaped apex of the aedeagus. DESCRIPTION: Size: Length 6.5 mm; width 2.8 mm. Integument: Cranium, thorax, legs, and abdomen cyanescent; elytra piceous. Vestiture: Integument vested predominantly with dark setae, few pale setae; metepisternal, sutural, and elytral setal tufts moderately developed; patches of middiscal elytral setal small. Head: Width across eyes narrower than width across pronotum (29:34); finely punctate; eyes subspherical, moderately convex, antenna as in figure 65. Thorax: Pronotum subequal in width and length, narrower than elytra across humeri (  DIAGNOSIS: Specimens of this species superficially resemble those of A. immarginatus (Chevrolat). In specimens of batesi, however, the elytral middiscal setal tuft ( fig. 179) is more developed and the tegmen of the male genitalia is not sagittate as is the case in specimens of A. immarginatus (Chevrolat).
VARIATIONS: The specimens examined did not vary appreciably.
NATURAL HISTORY: Specimens were collected in October and November (Brazil); two with a black light trap.
DISTRIBUTION (map 15): Found most frequently in the environs of the Amazon Basin of Brazil.

Aphelocerus ebenus, new species
VARIATIONS: There is some variation in the width of the elytral middiscal setal tuft; in one female specimen, the posterior elytral setal patch is very broad.
NATURAL HISTORY: The available specimens were collected from the type locality in May, at 600 m. Other specimens were collected in April, May, July, November, December, and January. J. Rifkind and H. Lezama captured one specimen by beating a fallen tree of Brosimum alicastrum.
DISTRIBUTION (map 12): Known from central Costa Rica to central Panama.
ETYMOLOGY: The trivial name, catie, is a noun in apposition and refers to the type locality. CATIE is an acronym for ''Centro Agronómico Tropical de Investigación y Enseñanza''.

Aphelocerus monteverde, new species
Figures 72, 177, 214; map 21 from which they may be distinguished by having the anterior patch of the middiscal setal tuft only slightly larger than the posterior patch. In A. arenatus, n.sp., specimens the anterior patch is twice as large as the posterior patch.
VARIATION: The available specimens did not vary appreciably.
NATURAL HISTORY: Specimens were collected during May, June, July, and August at altitudes ranging from 1040 to 1500 m.
DISTRIBUTION(map 21): Known only from northwestern Costa Rica. ETYMOLOGY: The trivial name monteverde is a noun in apposition and refers to type locality. DIAGNOSIS: These beetles may be distinguished from other specimens that have the cranium and pronotum cyanscent by having the pronotal disc coarsely punctate anterior to a feebly impressed anterior transverse depression, and the elytral discal setal tuft ( fig.  173) is comprised of a large anterior patch whose setae are directed anteriorly and a very small posterior patch comprised of only a few posteriorly directed setae. DESCRIPTION: Size: Length 5.0 mm; width 2.0 mm. Integument: Cranium, pronotum, pterothorax, legs, and abdomen cyanescent; elytra piceous. Vestiture: Head, prothorax, elytra, and protibia vested with predominantly dark setae, pterothorax, femora, and meso-metatibiae vested profusely with pale setae; tarsi vested with dark setae; epipleural margin vested densely with pale setae; elytral setal tuft bipartite, with large anterior patch and small posterior patch. Head: Width across eyes feebly narrower than width across pronotum (35:38), finely punctate; interocular depressions and frontal umbo shallow; eyes subspherical, moderately convex; antenna as in figure 70. Thorax: Pronotum equal in width and length (38:38), considerably narrower than elytra across humeri (38: 50), disc in front of anterior transverse depression coarsely punctate, side margin moderately arcuate, feebly incised by anterior transverse depression; elytra moderately convex; depth at humerus 22, greatest depth in posterior half 28, humeral umbo prominent. VARIATION: The available specimens did not vary appreciably.

Aphelocerus arenatus, new species
NATURAL HISTORY: Specimens were collected by beating, in May; one on a flowering tree; one at 1200 m. One additional specimen was collected in July.
DISTRIBUTION (map 21): Known only from central Costa Rica. ETYMOLOGY: The trivial name is comprised of the Latin arena (a place for games) and the Latin suffix -tus (pertaining to). I refer to the athletic fields at the University of Costa Rica from which some of these specimens were collected. Figures 32, 80, 151, 180, 273;map 22 HOLOTYPE: Male. Venezuela, Caracas, Valey, 11-VI-1992, L. R. Reynolds (FMNH). (Specimen point mounted; pygidium, sixth visible sternum, and hand printed sex label affixed to paper point; support card, white; locality label, white, machine and hand printed; collector label, white, machine printed; FMNH repository label, white, machine OPITZ: APHELOCERUS printed; holotype label, red, machine printed; holotype label, red, machine printed; plastic vial with aedeagus.) PARATYPES: None. DIAGNOSIS: In comparison to other members of the batesi group, the elytra of this beetle are atypically shallow ( fig. 32), the elytral middiscal setal tuft ( fig. 180) is comprised of two very small patches, and the antennal club is unusually large.
NATURAL HISTORY: The only available specimen was collected in June.
DISTRIBUTION (map 22): Known only from the type locality.

Aphelocerus anticus, new species
DIAGNOSIS: In specimens of this species the elytral discal setal tuft ( fig. 178) is com-prised of one patch whose setae are directed anteriorly.
VARIATION: The available specimens did not vary appreciably.
NATURAL HISTORY: Specimens were collected during May, June, and December at 680 m; another specimen was taken (670-762 m) in a forest field.
DISTRIBUTION (map 22): Known only from central Ecuador.
ETYMOLOGY: The trivial name anticus (in front) is a Latin adjective used here to refer to the anterior orientation of the setae of the elytral middiscal tuft. Figures 35, 36, 64 PARATYPES: Two specimens from the same locality as the holotype (WOPC, 2). NO. 293 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY DIAGNOSIS: The flecklike appearance of the setal tuft on the elytral disc (figs. 35, 36) will conveniently distinguish the members of this species. Also, the pronotal side margins (fig. 36) are boldly arcuate giving the pronotal disc a subspherical dorsal profile, a unique configuration of the pronotum in the batesi group.
VARIATION: The available specimens did not vary appreciably.
NATURAL HISTORY: The available specimens were collected by beating at 2103 m.
DISTRIBUTION: Known only from Honduras.

Aphelocerus protenus, new species
DIAGNOSIS: In specimens of this species the elytral humeral umbo is very prominent and the elytral discal setal tuft is a single diagonal patch ( fig. 171); the setae of the tuft are all decumbent and directed anteriorly.
NATURAL HISTORY: Specimen were collected in May, June, July, and December.
VARIATION: No noteworthy variation was observed among the specimens examined.
NATURAL HISTORY: Specimens were collected in January, May, June, and July, at altitudes ranging from 1000 to 1400 m. Two specimens were captured by beating roadside vegetation.
DISTRIBUTION (map 25): Known only from the Costa Rica Provinces of Guanacaste, Puntarenas and Cartago; some from Monteverde.

PANUS GROUP
VARIATION: The specimens examined did not vary appreciably.
NATURAL HISTORY: One specimen was collected in November.

Aphelocerus formicoides, new species
DIAGNOSIS: These small beetles (4 mm) have a distinct transverse concavity behind the well-developed humeral umbo of the elytra (figs. 45, 47). Also, the elytral disc has seven shallow, longitudinal carinae behind the humeral umbo.
VARIATION: The longitudinal carinae on the elytral disc vary in their strength.
NATURAL HISTORY: The available specimens were captured in May and June. Ed Giesbert collected six specimens at 800 m and one at 600 m near La Ceiba, Honduras. J. Rifkind and P. Gum collected two specimens by beating broadleaved hardwoods at 525 m.
DISTRIBUTION (map 23): This Central American species has been collected from southern Mexico, Honduras, and Belize.
ETYMOLOGY: The trivial name formicoides is a compound Latin adjective from the feminine formica (ant) and the suffix -oides (likeness). I refer to the ant like appearance of these beetles. Figures 200, 201, 226;map 25 HOLOTYPE: Male: Mexico, Veracruz, E slope Vol. San Martin Tuxla, 2200Ј, July 5, 1994. (Specimen point mounted, sex label affixed to paper point, white, machine printed; support card, white; locality label, white, machine printed; FSCA repository label, white, machine printed; holotype label, red, machine printed; plastic vial with aedeagus and abdomen).
VARIATION: The four specimens examined did not vary appreciably.
NATURAL HISTORY: The holotype specimen was collected during early July, whereas two paratype specimens were captured during early May, at 670 m and 945 m. One additional paratype was captured during April at the Biological Station of Los Tuxtlas.
DIAGNOSIS: The members of this species have the elytra polished, devoid of shallow longitudinal ridges, the pronotal tuft is absent, and the elytral apical angle is acute. These features will distinguish A. chelonus, n.sp., members from those of other species with the antennal apex testaceous.
DIAGNOSIS: The antennal apex of these beetles is testaceous, which is also a characteristic of some other species across species-group lines. Among the members of this species complex, cheliferous specimens may be identified by having the elytral surface polished, the outer margin of the elytral apex obtuse, and the side margins of the pronotum feebly convex.
VARIATION: Elytral coloration varies from black to piceous and the basal half of the pronotal disc varies in the number and structural development of the transverse wrinkles. The antenna apex is less testaceous in some specimens. Also, there is some variation in the prominence of the transverse subapical depression of the pronotum, humerus, posthumeral margin, lateral coompression of the elytra, and longitudinal elevations of the elytral disc.
NATURAL HISTORY: Specimens were captured in June, July, and in September, at altitudes ranging from 914 to 1493 m.
DISTRIBUTION (map 21): These specimens have been most abundantly collected from the Atlantic slopes of the Sierra Madre Oriental, but it is also known from the isthmus of Tehuamtepec.
MATERIAL EXAMINED: I examined 18 specimens from Mexico: Veracruz: 10 km N Fortin, 21-29-VII-1976, E. Giesbert (Wolcott, 1910: 357) which he later rejected as a secondary homonym of Clerus nitidus (Chevrolat, 1843: 25), and replaced it with the Adelphoclerus fulgidus (Wolcott, 1927: 73  NATURAL HISTORY: Specimens were collected in January-March, May-July, November, and December at altitudes ranging from 152 to 1800 m. Most of the beetles were taken in June and July. I collected 13 specimens by sweeping herbaceous hedge growth on a ravine summit adjacent to Rio Renvantazon, in Turrialba, Costa Rica. In association with these specimens, I collected 14 weevils of a Myrmex species that share a striking structural similarity with the clerids. The similarity is so profound that they are almost indistinguishable in dorsal view (compare figs. 163, 164). When observed alive, the two groups of beetles are readily set apart by differences in locomotion. The weevil's gait being sluggish when compared to the scurrying movement of the clerids. Nevermann captured one specimen in flight in January near Limon, Costa Rica, and D. Englemann found one specimen by beating epipytic vines of an Arum species. J. Rifkind and H. Lezama collected two specimens by beating fallen trees (Brosium alicastrum). One of these beetles was collected by Malaise trap and one on dead wood. D. R ETYMOLOGY: The trivial name inbatus is a Latin compound adjective that stems from the prefix -in (without) and batus (bush). I refer to the absence of a well-defined setal tuft on the frons present in specimens of closely related species.

Aphelocerus eriodes, new species
Map 26 HOLOTYPE: Female. Ecuador, Pichincha, 17 km E Sto. Domingo, Dec. 23-28, 1989, E. Giesbert (FSCA). (Specimen pin mounted, sex label affixed to support card, white, machine printed; locality label, white, hand printed; FSCA repository label; holotype label, red, machine printed; plastic vial with abdomen and aedeagus.) PARATYPES: None. DIAGNOSIS: The dense distribution of dark decumbent 2Њ setae on the pronotal and elytral disc will distinguish the members of this species from other specimens of the myrmecoides species group.
VARIATION: The available specimens are quite homogeneous.
NATURAL HISTORY: Frode Øedegaard collected the type series as part of his research involving canopy insects. The holotype was collected on flowers of Nectandra purpurascens. Other specimens were captured by beating canopy vegetation of Maranthes panamense, Calophyllum longifolium, Brosimum utile, Inga cocleensis, and Nectandra purpurascens.
DISTRIBUTION (map 25): Known only from the type locality.
ETYMOLOGY: The specific epithet is a compound name that stems from the Latin prefix -dis (without) and the Latin capillus (hair). I refer to the absence of the pronotal tuft in the members of this species.

EVOLUTIONARY CONSIDERATIONS
For most of this study, I could not postulate with confidence the monophyly of Aphelocerus nor could I identify the genus with any particular sister lineage. No synapomorphic characteristic among the species had been found during the descriptive phase of the work. I did have some suspicion that the black coloration of the integument, in combination with as assortment of arrange-ments of short silvery setae, might be of some assistance in this regard. Near the end of the revision, however, and while filling a few moments with identification work, to my great delight and quite by accident, I discovered a very obscure trich ( fig. 257) near the elytral apex of these beetles. I had found what eluded me for more than 10 years of research, a suprageneric-level synapomorphy, involving Aphelocerus and several New World clerine genera. I think most cleridologists would agree that I had found the proverbial phylogenetic needle in the checkered beetle haystack. It is just that difficult to find suprageneric synapomorphies within the Cleridae.
A sister taxon of Aphelocerus had also been very elusive. This, despite an extensive outgroups survey of taxa of the subfamily Clerinae and particularly those of the members of the New World Enoclerus. It has always been my impression that systematists carry a ''perfectionistic gene'' and very reluctantly publish systematic papers with overly loose ends in statements of kinships. I felt that way after completing the character matrix for the phylogenetic analysis. The lack of ''rooting'' to a relative, after more than a decade of work, made the whole work seem incomplete. Then, in the final preparation of the manuscript, my good friend and colleague Lee Herman suggested that I might check once more for a sister group, which if found, would facilitate his assistance with operation of the Hennig 86 program. Having done this sort of tedious search several times before I hesitated at the suggestion, but did so and within five minutes found the elusive sister group. I found an elytral trich among most members of the New World clerine genera with well-developed tarsal denticles; for example, such genera as Placopterus, Caestron, and Enoclerus.

CHARACTERS SELECTED FOR PHYLOGENETIC ANALYSIS
Thirty-eight adult characters of Aphelocerus Kirsch and the outgroup genera Placopterus, Caestron, Perilypus, Colyphus, Sallea, Blaxima, Phonius, and Systenoderes were used in the species-group analysis. All of the outgroup genera involve New World clerine genera that I consider to be the most closely related taxa of Aphelocerus. Character states delsignated as ''0'' are considered plesiomorphic whereas those given a value from ''1'' to ''6'' (in the case of transformation series) are judged apomorphic. NO. 293 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY

PHYLOGENETIC ANALYSIS
A character matrix was coded for the 15 species-group taxa (the outgroup involves representative species of more than eight generic taxa) listed in table 1 and encoded into Hennig 86. The analysis yielded one phylogenetic tree ( fig. 278) with a length index of 32, consistency index of 84, and retention index of 85.

PHYLOGENETIC SCENARIO FOR THE EVOLUTION
OF APHELOCERUS AND ITS SPECIES GROUPS It is hypothesized that ancestral Aphelocerus diverged on the land mass comprised of the ancient Mexican/Mayan blocks, that is, somewhere after the major Tertiary tectonic events. An earlier evolution of the genus is not supported by features of the external or internal morphology, or by any other line of evidence, in that an earlier Tertiary origin for Aphelocerus would likely have generated substantially more structural divergence than is presently known. Moreover, had aphelocerans been part of the great Tertiary tectonic events, the vicariant divisions and geographic shifts of the ancestral apheloceran populations would have provided tremendous evolutionary inertia, as has been demonstrated for other forms of life that ''went along for the ride'' during ancient Caribbean plate tectonics (Rosen, 1974(Rosen, , 1976Pregill, 1981;Hallam, 1981).
The extent of generic memberships of the outgroup ( fig. 278), based on the presence of the elytral trich, has not been fully established. However, it is clear that during the evolutionary ascension from ancestral species A towards ancestral Aphelocerus (ancestral species B), the elytral trich was retained. During this ascent, the ancestors of extant aphelocerans also evolved such novel characteristics as development of a clearly defined sutural tuft, and among most species, the consolidation of 2Њ setae into some sort of elytral tuft most prominently visible in the acanthus species group.
During the early evolution of apheloceran ancestor B, two major assemblages diverged. One of these ultimately evolved descendants characterized by aggregates of white 2Њ seta on the elytra. In the second lineage of this initial divergence of the apheloceran progenitor, and beginning with ancestor D, the elytra were transformed towards a more rotund configuration. It is suggested that this evolution, featured by a more compact, shorter, and more convex body form, represents a progression towards a mimetic life style involving spiders, ants, and Myrmex weevils. A gradual transition of convexity may be seen when one compares members of the panus species group with members of the scutellaris-myrmecoides lineages. Among these extant species groups one can clearly see the anatomical perfection towards ants as exibited by members of the formicoides species group that is hypothesized to be an offshoot of ancestral species L. Ancestral species L also generated a line whose body morphology became more compact and whose general fascies proceded towards a resemblance to leaf-inhabiting jumping spiders and weevils. The sister group relationship between the scutellaris species group and the myrmecoides species group is strongly supported by such conspicuous synapomorphies as digitiform parameres, presence of frontal and pronotal setal tufts, and a very strong evolution towards mimicry. In time, ancestral species M diverged to produce the scutellaris-myrmecoides species groups, any member of which converged towards the body plan of jumping spiders and/ or Myrmex weevils (compare figs. 163 and 164).
From the progenitor of Aphelocerus (ancestral species B) there apparently evolved a stem species (ancestral species C) that retained the plesiomorphic, more flattened elytral structural plan characteristic of the majority of the species in the genus. The divergence of ancestral species C evolved into a line in which the elytral surface became scabrous. It is hypothesized that eventually this line evolved into ancestral species E that, in turn, diverged to produce ancestral species G and H.
Ancestral species G generated the sister species groups coalitus and echinatus, both characterized by their retention of asetiferous punctations. Ancestral species H produced the ciliaris-bispineus lineage in which the 2Њ elytral setae demonstrate a trend towards consolidation. White 2Њ setal aggregates towards development of an elytral patch becomes progressively more prominent as one proceeds towards the irroratus-yungas species-group members.
In summary, there are three major evolutionary trends among the extant species of Aphelocerus. The first, and most conspicuous, involves the progressive increase of elytral convexity as we proceed from the panus species group and end with the scutellaris species group. The second trend involves the development of 2Њ setae on the elytra as is seen from the coalitus species group to the bispineus species group. Lastly, there is a progressive consolidation of 2Њ setae into setal patches on the elytra, which reaches its most complex development among the acanthus species-group specimens. Then, there is a curious characteristic reversal; one hypothesizes a reduction of the posterior patch of the 2Њ elytral setal tuft. This reversal is most clearly evidenced in the batesi species group.

ZOOGEOGRAPHIC CONSIDERATIONS
Many outstanding advances have been made in biogeography from the pioneering Darwinian concept of center of origin and dispersal. The panbiographer Croizat (1964) advanced the idea that contemporary macrobiotic distributions may be placed into historical context by the establishment of faunal tracks, tracks that faunistically unite intercontinentally and thus potentially foretell, or suggest, patterns of historical distributions of species ancestral to the extant species under study. Faunal tracks are established by plotting corroborative distributional linearities of distantly related faunas and floras. Rosen (1978: 160) refined Croizat's concepts into a methodology called vicariance biogeography whereby tectonic events are acknowledged to fragment ancestral biotas into geographical separation. Subsequently, these now separated biotal fragments may or may not respond evolutionarily following the vicariant event. If evolutionary inertia does take place, that is, if through natural selection, or through any other process involved with speciation, the biota fragmentation evolves novelties, and possibly obscure ancient synapomorphies, then the kinship relationship may well be inferred with usage of the vicariance biogeographical model. In essence, the vicariance concept involves the fragmentation of ancestral faunas towards an insular existence of the resultant vicariants.
With a focus on Mexico and Central America, Halffter (1987) suggested that the extant insect distributions of the Mexo-America (as defined by fig. 282) and Nuclear Central American (as defined by fig. 284) faunas are explainable via transitional zoning. Halffter's biographic concept considers temperate and tropical montane habitats the primary basis for northern and southern encroachments of insect biotas into the aforementioned landmasses. More recently, Liebherr (1991a) applied cladistic biographical methods to derive general area cladograms for the montane areas of Mexico on the basis of cladistic analyses of the carabid genera Elliptoleus and Calathus.
Despite these important advances in biogeography, I am compelled to reiterate an earlier thought about the use of biogeograph-ic methods: ''Irrespective of biotic or taxonomic level, it is the nature of the available data that usually determines the approach to historical zoogeography'' (Ekis, 1977: 126), particularly among systematic entomologists who often struggle with a paucity of distributional records.
Lastly, cladistic biogeography suggests that distributions of extant taxa reflect results of physiogeographically based historical vicariances. This concept of biogeography is more likely to be supported by ancestral or more primitive extant taxa simply because there has been more time to evolve phylogenetically useful characteristics that can support of refute biogeographical hypotheses. In many instances, however, the cladistic biogeographical model is difficult to apply when one deals with species-level faunas that have undergone, or are undergoing, rapid evolution in relatively recent geologic history. In such cases, there has not been sufficient time for establishment of synapomorphic diversity upon which to base hypotheses of evolution or historical biogeography.

GEOPHYSICAL ORISMOLOGY
In biogeographical analyses it is important to define geophysical parameters. How one partitions the research terrain is often dependent on the vagility of the organism under consideration, the extent of ecological specialization of the species, the geographical extent to which the research animal has been collected, and the extent of the motivation of the investigator to provide extant/historical explanations of currrent distributional patterns. In the recent decades, there has been a flurry of important discussions relevant to the geophysical properties if Middle America (Malfait and Dinkman, 1972;Keigwin, 1982;Coney, 1982;Burke, et al., 1984;Weyl, 1966;and Donnelly, 1988). Moreover, in Systematic Entomology, the works of George Ball (e.g., 1978) and his students (Erwin, 1970;Whitehead, 1972;and Noonan, 1973), and Liebherr (1988and Liebherr ( , 1991and Liebherr ( , 1991aand Liebherr ( , 1992and Liebherr ( , and 1994 have greatly advanced our thinking about Middle American insect biogeography. The above mentioned works, and others, have been important resources for my thoughts about Middle American checkered beetle biogeography. Checkered beetles are a particularly difficult group to analyse biogeographically because of the difficulties associated with their collection. They are rarely collected in great numbers, as a group are comprehensively involved in mimicry (Mawdsley, 1994), and are few in numbers per locality, and are sometimes associated with floral periodicity (Opitz, 2002: 241). However, I can state with confidence that most of the Middle American checkered beetle fauna is found most abundantly in midaltitude highlands, usually at about 1000 m. The prominent association of checkered beetles with temperate and tropical montane regions, in combination with some recent information about Middle American tectonics and historical orogeny, suggests, at least for checkered beetle biogeography, a subdivision of the New World into seven major divisions. These divisions although generally alligned with political boundaries are established to focus more on the major mountain ranges from which checkered beetles have been collected in abundance.
North America ( fig. 279): The northern continental landmass south to the political boundary with Mexico and corresponding roughly with the diminution of the more southern ridges of the Rocky Mountains.
Middle America ( fig. 280): The landmass extending southeast from the United States to the southeastern highlands of the Cordillera de San Blas of Panama. South America (fig. 281): The southern continental landmass extending east and south from Panama and more or less in its westernmost region, corresponding to the distribution of the Colombian-Venezuelan Andes to the southern foothills of the Chilean Andes.
Mexo-America ( fig. 282): The terrain south of the United States and approximately compatible with three great mountain chains, the Sierra Madre Occidental, the western component of the Transvolcanic Sierra, and to the southern foothills of the Sierra Madre del Sur. This subdivision ends at the southermost limit of the isthmus of Tehuentepec and geologically consists of the Mesozoic Mexican Block (Donnelly, 1988: 17).
Central America ( east of the Isthmus of Tehuantepec, then extending eastward and southward to the border of Colombia. The terrain includes the Talamancan range of Costa Rica and Panama and the Cordillera of San Blas in eastern Panama. The northern half of this landmass remained above sea level thoughout the Cenezoic, whereas the southern half was submerged throught the majority of the Tertiary (Savage: 1982: 465).
Nuclear Central America ( fig. 284): The portion of Central America extending from the Isthmus of Tehuentepec southeastward to the highlands of eastern Nicaragua. In essence, this terrain roughly corresponds to what has been called the Chiapas Complex (Ball and Shpeley, 2000), and involves the pre-Mezozoic Mayan and Choris Blocks. Although there was considerable tectonic rearrangement of these crustal areas during the development of the Caribbean portal, convention has it that they were connected to the Mexican Block and consistently above sea level during the Tertiary. It is believed that the Choris Block connected to the Mayan Block at the end of the Cretaceous and tectonocally acquired its present position at about 30 million years ago (Donnelly, 1988: 21).
Insular Central America ( fig. 285): The southern portion of Central America located between southern Nicaragua and Colombia and involving the Costa Rican-Panamanian highlands of Sierra Talamanca and the Panamanian Cordillera San Blas. It is widely known that this terrain was submerged during the greater part of the Tertiary and formed the Pacific and Atlantic portal. The closure of this portal began some 25 million years ago (Keigwin, 1982;Donnelly, 1988), and allowed interchanges of flora and fauna between North America, Mexo-America, Nuclear Central America, and South America.
As a group, the aphelocerofauna is in a rapid state of evolution, as the general anatomical coherence within the group suggests. The species members of the batesi and yungas species groups are particularly similar in general anatomy. It is unlikely that their present distributions can be linked to Tertiary orogenic and/or tectonic events. In the genus, there are an outstanding number of cryptic species. In particular, there are a variety of cryptic species within the batesi species group whose members exhibit the most extensive geographic distribution within the genus. Cryptic species are common in other apheloceran species groups as well. Therefore, it is unlikely that the present distributions of the more recent apheloceran species groups can be linked to tertiary orogenic and/ or tectonic events. Moreover, of the 66 species presently recognized, fully 54 are confined to single mountain complexes (see figs. 286, 287). When one deals with such recent faunas, area cladograms based on historical geologic events must give way to models implementing biographical methods of dispersal and transitional zoning.
The limited range of many of the species suggests that Aphelocerus is undergoing rapid evolution, principally in isolation, in montane Middle American ( fig. 286) and montane northern South America ( fig. 287) highland complexes. In my view, this suggests that the ancestral apheloceran divergences occurred after the principal Tertiary tectonic events. Therefore, in an attempt to present some beginnings of a biogeographical analysis of this genus, I will implement the ''transitional zone'' method as defined by Marshall and Liebherr (2000) and proposed by Halffter (1987).
However, when dealing with the ancestors of Aphelocerus, in connection with the distribution of extant taxa closely related to that genus, some preliminary historical biogeographical comments might be worthy of discussion. Distributional evidence suggests that ancestral Aphelocerus evolved on an ancient Middle American terrain, probably on what is commonly referred to as the Mexican and Mayan Blocks. These were prehistoric crustal areas that fused tectonically to the northern continent as far back as Albanian time, some 100 million years ago (Donnelly, 1988: 19). These blocks must have been exceptionally fertile grounds for some clerine lineages as today regions that correspond to these ancient land masses harbor a variety of monotypic taxa that undoubtedly represent surviviors of a much more diverse Tertiary fauna.
Perhaps, many of these ancestral kindreds of Aphelocera, which led to such older groups as Blaxina and Sallea, succumbed to the Yucatanian Bolide impact thought to have occurred at the end of the Cretaceous (Alvarez and Asaro, 1990). Having survived the Bolide impact, ancestral aphelocerans, and those of the lesser speciose cousins, apparently proved more adaptable to the incipient habitats that persisted following the Bolide impact. Aphelocerans probably flourished during the post Bolide impact periods, as did such genera as Colyphus, Perilypus, and Placopterus. These genera, along with the very speciose Enoclerus, proceeded to proliferate into available niches on the more favorable southern habitats. Such habitats would have been provided by tectonic events such as the addition of the Chortin Block to the Mayan Block thereby increasing the area of more tropical environs and completing the development of what has come to be known as Nuclear Central America.
In time, there would have been the closing of the Panamanian portal, allowing a southern apheloceran dispersal that proliferated a number of species across species group lines, and generated such derived groups as the autochtonous sculptillus and myrmecoides species groups. It is difficult to add credible biographical comments about the South American aphelocerofauna. On the basis of what is known, it seems that this fauna stems from multiple southern extensions of Middle American elements. What can be stated with confidence, however, is that these tentative statements about Aphelocerus biogeography will have to be reevaluated when the South American aphelocerofauna is more thorougly known. I believe that there are vastly greater number of apheloceran species in South America than have heretofore been dicovered.