Revision of the genus Psix Kozlov & Lê (Hymenoptera: Scelionidae)

The genus Psix Kozlov & Lê (Hymenoptera: Scelionidae) is revised from a worldwide perspective. Twelve species are described as new: annulatus [Cameroon], asper [Uganda], aulax [Australia], confluus [Sri Lanka], flavicoxa [Ivory Coast, Zimbabwe], fusm [Australia], lacunatus [Pakistan east to Taiwan, south to Australia], metopa [Australia], rasilis [Ivory Coast, Gambia], sulcifer [Malaysia], viriosus [India east to Philippine Is.] and watshami [E. Africa, Madagascar] . Psix abnormis Kozlov & Lê [W. Africa east to at least India], glabris‐crobus (Girault) nxomb. [Australia], olympus (Dodd) n.comb. [Australia], saccharicola (Mani) n.comb. [India], striaticeps (Dodd) n.comb. [W. Africa east to India, Madagascar] and tunetanus (Mineo and Szabó) n.comb. [Tunisia, Gambia, Ivory Coast, Saudi Arabia, S.W. Nearctic, Venezuela] are redescribed. An identification key for the species of Psix is presented. The relationships among species are discussed. The earliest derived species are generally found in Australia and southeast Asia. The more apomorphic species occur generally in Africa, southwest Asia and India. The distribution of Psix tunetanus has possibly been influenced by man. Details of the relationship with Trissolcus and Archi‐phanurus are unclear; the position of Psix within the subfamily is therefore also obscure.


Introduction
The search for effective biological control agents against bugs of the superfamily Pentatomoidea (Heteroptera) has often focused on their egg parasitoids, and, in particular, on the species of the subfamily Telenominae (Hymenoptera: Scelionidae; see, e.g., Brown, 1962;Safavi, 1968). Biological and systematic research on these wasps has focused on the large genera Telenomus Haliday and Trissolcus Ashmead (= Asolcus Nakagawa, Microphanurus Keiffer). We present here information on another, relatively unknown group of telenomines: the genus Psix Kozlov divided into two parts (Fig. 25): the dorsal portion is continuous with, and has the same costate sculpture as the lateral portions of the metanotum. The ventral lip (VL) (Fig. 25) is variable in sculpture; it may be coarsely areolate-rugose ( Fig. 2 l ) , finely punctulate (Fig. 22) or smooth (Fig. 25). The sculpture of the frons of several species is dominated by a few stronglydeveloped longitudinal carinae (Fig. 3 ) : the central keel (CK) (Masner, 1980); the orbital carinae (OC), continuous with the inner orbits and extending ventrad toward the mandibles; and the submedian carinae (SC), located between t h e orbitals and the central keel, and, in species such as P.vrriosus, defining the lateral margins of the antennal scrobes. The genal carina (GC) (Fig. 13) arises at the base of the mandible and continues dorsad on the gena, generally not farther than the upper edge of the eye. The acetabular field (AF) (Fig. 15) is a small area of coriaceous microsculpture on the mesepisternum near the dorsal apex of the acetabular carina. The intercaxal space (ICS) (Fig. 50) is the ventral region of the mesepisternum between the fore and mid coxae. There is a line of foveae on the mesopleuron that we are unable to homologize with those of any other telenomine group.
This lies posterior to the foveae we believe represent the mesopleural suture (MPS) (Fig. 13) and are referred t o as postepimeral foveae (PF). The meiapleural carina (MC) is generally indicated only by a line of foveae extending from the posterior margin of the metapleuron toward the propodeal spiracle (Fig. 14). On the second metasomal sternum (52) are two densely setose areas of finely coriaceous or granulose microsculpture; these are referred to as setal fieZds (SF) (Figs. 31,32). The function of these unusual structures is unknown.
The following generic description serves both t o distinguish Psix from other telenomines and to summarize character states held in common by a majority of species. These characters are therefore not further discussed in the individual species descriptions except as they differ from the most common condition.

Discussion
The only other telenamine genus known with the bifurcate central keel and fanlike facial carinae is Archiphanunis Szabd. Psix may be most conveniently distinguished from it by the black T1, well-developed setal fields on S2 and contiguous fore and mid coxae. Those species of Psix in which the intercoxal space is present may be separated from Archiphanurus by the presence of crenulae flanking the mesopleural carina anteriorly and the presence of a netrion on the pronotum. Nixon (1938) was the first to appreciate the unusual character states of Telenomus striaticeps Dodd and to suggest that it may represent a distinct genus. Psix was not described until 1976 by M. A. Kozlov and LG X u k Hub to contain their new species from Afghanistan, P.abnormis. In the time since the generic description was published there has been some confusion of Psix with Archiphanurus and Aporophlebus Kozlov.
Kozlov & L& (1977) correctly treated Aporophlebus as a junior synonym of Telenomus (type-species Aporophlebus aporus Kozlov, examined by us). Masner (1980) provided characters by which to separate the species of Psix then known from those of Arckiphanurus.
We have not examined the type material of the many species of Telenominae described from Australia by A. P. Dodd. The taxonomy of the subfamily in the early part of this century was based largely on the relative length, width, number and coloration of antennomeres. The emphasis has subsequently shifted away from these characters. Consequently, it is impossible to determine on the basis of the original descriptions which of Dodd's species of Telenomus, or possibly even Trissolcus, should be classified in Psix.
Discovery of species from Australia and southeast Asia has forced us to expand our concept of the generic limits of Psix to the point that it is now impossible to cite a series of characters that will serve to separate all Psix from Archipharnurus. We feel, nevertheless, that Psix is a convenient and identifiable unit and, for the time being, can be treated as a distinct genus. Further study of the relationships within the Telenominae will eventually demand a reclassification in order to be consistent with the criterion of monophyly. Whether Psix will then remain standing as a separate genus or will be subsumed within a larger one (e.g. Trissolcus) is uncertain. -Frons and scutellum usually with well-developed sculpture covering entire surface ( Fig. 1 2 ) ; acetabular field glabrous; SZ sulci nearly continuous posteriorly (Fig. 3 5 (Girault, 1926) c0mb.n. lantnatus sp.n. metopa sp.n. olympus (Dodd, 1913) c0mb.n. rasilis sp.n. sacchavicok (Mani, 1941) c0mb.n. striaticeps (Dodd, 1919) c0mb.n.
Remarks. Psix abnurmis may be distinguished from the other species of the genus with yellow or light brown radicle (watshami, viriosus, confluus, olympus group) by the circular pattern of sulci on S2. This species may also be distinguished from those with closely approximated or continuous S2 sulci (rasilis, annulatus, flavicoxa, saccharicola) by the yellow radicle and the highly reduced setal fields on S2 (without microsculpture, a small area of granulose sculpture is retained in annulatus).
r e (1 982) has recently described a species of Psix from Vietnam. In the English summary he states that this species has the base of the scape brown; nothing is said about the colour of the radicle. On the basis of the illustration of the head and S2 we suspect this name, P.contemporalis, t o be a junior synonym of P.abnormis.
Remarks. Psix annulatus may be distinguished from those species of the genus with closely approximated or continuous sulci o n S2 (rasilis, flavicoxa, saccharicola, abnormis) by the combination of the black radicle, yellow coxae, reduced setal fields on S2, and the unique U-shaped pattern of the sulci. The microsculpture on S2 in addition gives the ridges the distinctive appearance of braided rope. area between orbitals and submedians granulose, with weak transverse wrinkles; area between submedians and central keel transversely carinate, carinae dorsally reaching keel, ventrally extending only about halfway to keel, otherwise this area smooth; frons width subequal to eye height; mesoscutum rugose throughout; notauli present, short, somewhat obscured by coarse surface sculpture (Fig. 23); scutellum with same sculpture as mesoscutum; dorsellum strongly protruding, ventral lip coarsely areolate-rugose (Fig. 21); netrion present, narrow, poorly-defined (Fig.  18); acetabular field and anteroventral portion of mesepisternum setose (Fig. 15); mesopleural carina indicated posteriorly by line of foveae, indicated anteriorly only by few foveae ventrally (Fig. 15), with no or only weakly raised crest; postepimeral foveae reduced to 2-3 impressions dorsally, 1 shallow impression near midpoint of height of mesosoma (Fig. 15); anterior extension of metapleuron toward mix coxa long, acute; course of metapleural carina indicated by line of foveae; T1 with 1-2 pairs of sublateral setae; T2 longitudinally rugulose (Fig. 26), rugulae weak apically, at most with only faint indication of crossstriae, surface of sclerite with numerous setae; lateral sulci of S2 broadly separated posteriorly (Fig. 33); setal fields large; central area of S2 between sulci otherwise with scattered setigerous punctures, each separated by 1-3 times its own diameter, anteriorly punctures more widely separated.
Host. Pent atomoidea. Material examined. Remarks. This species may be distinguished from the other members of the genus possessing notauli (sulcifer, viriosus, confluus) by means of its black radicle; it may be separated from those species with both a black radicle and well-developed submedian carinae (gEabriscrobus group, lacunatus) by the combination of the occluded intercoxal space, netrion narrow or absent, postepimeral foveae reduced, no areolae on the scutellum, and dark coxae. Psix wtlax sp.n. (Fig. 46) Length 0.9 m m ; radicle and scape yellow; coxae brown; central keel not reaching median ocellus, antenna1 scrobes delimited dorsally by transverse rugae; submedian carinae well developed (Fig. 46), extending as far dorsad as central keel; frons above and laterad of scrobes irregularly longitudinally rugose; area between orbital and submedian carinae narrow, with only single longitudinal wrinkle on each side; transverse rugae o n frons restricted t o dorsal apex of scrobes; frons width subequal to eye height; right mandible with two strong, equally developed acute teeth (left mandible not visible); dorsellum produced medially, ventral lip coarsely punctate; netrion present, narrow; acetabular field and anteroventral portion of mesepisternum setose; mesopleural carina flanked b y crenulae both anteriorly and posteriorly; anterior extension of metapleuron toward mid coxa distinct, acute; course of metapleural carina indicated by row of foveae; no sublateral setae on T1; T2 longitudinally costate, microsculpture and costae effaced near midline; T2 with few setigerous punctures laterally; sulci on S2 broadly separated posteriorly; setal fields well developed ; area between sulci in posterior half of S2 coarsely and evenly coriaceous, setose, but without distinct punctures at setal bases (as in P.gZabriscrobus), S2 smooth in anterior half.
Host. Unknown. tion of notauli, somewhat obscured by surrounding sculpture; longitudinal furrow arising medially from scutoscutellar sulcus extending short distance anteriorly, less than one-fourth length of mesoscutum; disc of scutellum with weak impression posteromedially, depression granulose, without surface rugae, dorsal edge of marginal rim drawn u p into point at this position; dorsellum strongly protruding, ventral lip coarsely punctate; netrion present, broad; fore and mid coxae separated by short b u t distinct intercoxal space; acetabular field and anteroventral portion of mesepisternum setose; mesopleural canna flanked by row of contiguous foveae posteriorly, by poorly dif-ferentiated foveae anteriorly, with distinct raised crest; anterior extension of metapleuron toward mid coxa long, acute; course of metapleural carina indicated b y line of foveae; sublateral setae on T I absent; T2 longitudinally rugulose in basal two-thirds, apicad of midpoint of length of sclerite densely punctate, setose throughout; lateral sulci on 52 broadly separated posteriorly; setal fields well developed; area between sulci on S2 covered with large setigerous punctures, each separated by distance subequal t o or less than its own diameter.
Material examined. Remarks. This unusual species may be recognized among the other members of the genus with yellow or light brown radicle (viriosus, olympus group, watshami, abnormis) by the combination of the coarse sculpture of the ventral lip of the strongly protruding dorsellum, the lack of deeply incised, acute mandibular teeth, the presence of a narrow intercoxal space, and the extremely short notauli.  Host. Unknown. Material examined. Holotype 0: AUS-TRALIA: Northern Territory, Yuendumu, 15-3O.ix (AEI). Other material. These specimens are generally in very poor condition: some are broken, all are extremely dirty. Our concept of Psix fusus is based upon the single female from Yuendumu. Accordingly the following specimens have not been designated as paratypes. AUSTRALIA: 4 4, pentatornid egg mass, Queensland, Nappamerry, 6.xi. 1949 (Riek) (one without metasoma, one without head) (ANIC).
Remarks. This species may be separated from the other members of the glabriscrobus group by the lack of a distinct intercoxal space, the fore and mid coxae are contiguous, t h e normal condition in the genus. Psix fusus may be distinguished from the other species of the genus that possess both a black radicle and submedian carinae by the presence of a well-developed netrion, the lack of transverse rugae in the ventral portion of the scrobes, and by the failure of the central keel to reach t h e median ocellus.
This species is very similar t o P.glabriscrobus, the major difference being the presence of a distinct intercoxal space in the latter species. We eagerly wait the collection of further Australian material that may serve to test our hypothesis that this difference is one between species and not a case of intraspecific variability.
Psiv ghbriscrobus (Girault)  Remarks. Psix glabriscrobus may be distinguished from its sister species fusus by the presence of a narrow, but distinct intercoxal space. It may be separated from metopa by the shorter and stouter body and wings, by the presence of welldeveloped transverse elements in the sculpture of T2, and by the densely punctulate apex of T2. It may also be recognized among the other species with black radicle and submedian carinae by the welldeveloped netrion and the presence of the intercoxal space.
Host. Biprorulus bibax (Pentatomidae). protruding, ventral lip punctate; T 1 with one pair of sublateral setae; apex of T2 either weakly punctulate or smooth; T2 otherwise longitudinally rugose throughout (Fig. 2 9), with at most only weak indications of crossstriae; S2 (Fig. 34)  Remarks. This species may be separated from others in the genus with yellow coxae Cflavicoxa, annulatus) by the presence of distinct submedian carinae, punctate ventral lip of the dorsellum, and the narrow frons.
Psix lacunatus may be distinguished from those species possessing both a black radicle and distinct submedian carinae (asper, glabriscrobus group) by the lack of notauli and netrion, the weakly expanded and more finely sculptured dorsellum, and the absence o f foveae indicating the course of the metapleural canna.
Psir metopa sp.n. (Fig. 42) Length 1.4-1.6 mm; radicle black; scape yellow; coxae dark brown to black; submedian carinae well developed (Fig. 42); antenna1 scrobes delimited dorsally by transverse carinae; frons above scrobes with irregular longitudinal rugae; area between orbital and submedian carinae setose, setal bases strongly raised; frons width > eye height; genal carina parallel t o posterior orbit; dorsellum strongly produced medially, ventral lip punctate, deeply excavate dorsally; netrion present, narrow; intercoxal space present, narrow; acetabular field and anteroventral portion of mesepisternum setose; mesopleural carina flanked by crenulae both anteriorly and posteriorly; anterior extension of metapleuron toward mid coxa long, acute; course of metapleural carina indicated by line of foveae; no sublateral setae on T 1 ; T 2 longitudinally costate, with no indication of transverse elements, sparsely setose laterall y ; lateral sulci on S2 broadly separated posteriorly; setal fields large, located in posterior half of sulci, not extending beyond apex of sulci; area between setal fields smooth, with setigerous punctures separated b y 3-4 times their own diameter; anteriorly sulci closely approximated medially, space between them with weak longitudinal wrinkles. Remarks. This species may be distinguished from the closely related P.gZabriscrobus by the lack of cross-striae on T2, apex of T2 weakly punctulate, and the more elongate body and wings.
Remarks. Psix rasilis may be distinguished from others in the genus with closely approximated, intersecting or continuous S2 sulci by its black radicle (yellow in abnormis), dark coxae (yellow in flavicoxa and annulatus), and punctulate ventral lip of the dorsellum (smooth in saccharicola and abnormis).

35)
Telenomus saccharicola Mani, 1941: 26. Holotype 9, INDIA: New Delhi, host, Length 0.6-0.7 mm; radicle black; scape yellow to yellowish-brown; coxae dark brown; frons (Fig. 12)  Remarks. PsLx SQCChQriCOh may be separated from tunetanus on the basis of the continuous sulci on S2; from watshami and abnormis by the dark radicle and the pattern of the sulci on S2 (compare Fig. 35 with Figs. 37 and 38); it may be separated from rasilis, annulatus and flavicoxa by the combination of the smooth ventral lip of the dorsellum and the darkened coxae.
One specimen from India (Bhorghat-Sangvi village, Bhatghar Dam, 70 km from Poona, near R. Joguati, Deccan Plateau [Mani, 19761) agrees with the specimens of saccharicokz described above except in colour characters. This specimen, in the collection of the USNM, is extremely dark in colour, appearing very similar to P.tunera-nus. It was collected in March 1962, as were the three females from Marudumalai above. We conclude that this represents only an extreme colour variant of saccharicola.
We have associated the type of Telenomus sachharicola Mani with this species through the assistance of Drs M. Farooqi and S. Ghai (IARI).
Remarks, Psix striaticeps may be distinguished from the closely related P.lacunatus by its lack of distinct submedian carinae, dark coxae, punctulate or finely striate ventral lip of the dorsellum, and the smooth anterior declivous portion of the mesoscutum. It may also be separated from the related P.rasilis by the wide separation of the S2 sulci posteriorly.
Remarks. Psix sulcifer may be separated from the other species of the genus possessing notauli by its deeply incised, acute, tridentate mandibles, the light brown radicle, and the lack of transverse sculpture within the antenna1 scrobes.
Remarks. Psix tunetanus may be distinguished from the closely related species saccharicola, rasilis, annulatus and flavicoxa by the broad separation of the sulci in the posterior portion of S2; the dark radicle of tunetanus will serve to separate it from both abnormis and watshami (radicle yellow).
The anomalous distribution of tunetanus deserves comment. As summarized above, this species is known in the Old World from Saudi Arabia, Tunisia, the Ivory Coast and Gambia; and in the New World from the southwestern U.S. (California, Arizona, New Mexico, Utah, Oklahoma, Texas, Illinois), northern Mexico (Sonora, Baja California Sur), and the Lake Maracaibo basin in Venezuela. On the basis of the distribution of other species of Psix, and the position of tunetanus in the cladogram, we have little doubt that this species originated in the Old World and has since spread into the New. We suggest that the range expansion has been connected with commercial traffic into the southwestern United Statesin support of this we note the large-scale importation of Mediterranean plants into southern California and neighbouring states in the past century. The Venezuelan population, by virtue of its isolation, may represent a second introduction. Lake Maracaibo is a major port of entry into the country, and the area immediately surrounding the lake is a dry enclave in the surrounding tropical habitat.
Remarks. Psix watshami may be distinguished from other Psix with a yellow or light brown radicle (abnormis, viriosus, confluus, olympus group) by the lack of distinct submedian carinae, the smooth ventral lip of the dorsellum, and the distinctive coriaceous sculpture of the scutellum (lacking the raised areolate-rugose sculpture typical for the genus). This species is named for the Rev. Anthony Watsham, whose extensive collecting in southern Africa has provided a great treasure of both Chalcidoidea and Proctotrupoid ea.

Phylogeny
A cladogram representing one hypothesis of the interrelationships among species of the genus Psix is presented in Fig. 5 1. The characters upon which this is based are listed in Appendix 1. Hypotheses of character polarity were derived using P.confZuus as the outgroup. This choice was made despite the fact that Archiphanurus is undoubtedly closely related to Psiw. Archiphanurus is a highly specialized genus in many respects and determination of homologies is often difficult. A subgroup of Trissolcus is probably the best candidate as an out-group, but our understanding of t h e systematics of that genus is as yet so fragmentary that this was not a practical option. We believe P.confluus is a relatively good choice as an out-group because it retains many character states that are probably plesiomorphic for t h e subfamily as a whole, i.e. widely found in the Teleasinae and tribes of t h e Scelioninae, viz setose lateral margins of T2, mesopleural carina present and flanked b y crenulae, mesoscutum and scutellum coarsely sculptured, notauli present, lateral ocelli connected t o inner orbits by a furrow. The implicit assumption, therefore, is that in character polarity hypotheses 'common equals primitive', but given the present state of our knowledge of the systematics of these groups we see no better alternative.
The cladogram figured is only one of several possible with a total length of 3 6 steps (excluding autapomorphies). We do not present this one as a definitive answer, but rather as a graphic illustration of some general characteristics of all of them. Two points are consistent. First, the species lacunatus, striaticeps, rasilis, flavicoxa, annulatus, saccharicola, tunetanus, watshami and abnormis form a monophyletic group, the lacunatus species group. The relationships within this group are consistent and illustrated in Fig.  51. Second, the species from Australia and southeast Asia generally cluster together near the base of the cladogram, in this example as two monophyletic groups, the olympus group (olympus, aulax, sulcifer) and the glabriscrobus group (glabriscrobus, fusus, meropa). These species do not always appear as monophyletic groups; the relationships among them (and asper and viriosus) are unclear as a result of widespread homoplasy, difficulties with using P.conj7uus as an outgroup, and the small numbers of specimens available for these species. The homoplasy in character 4, i.e. the presence on occlusion of the intercoxal space, is disturbing to us. Our understanding of both the inter-and intraspecific variation in Psix species from Australia and southeast Asia is, however, based upon a very small sample size. We anticipate that further collecting efforts will greatly help to clarify character state distributions among these species.
The more derived species of the genus, the Zacunatus group, are generally found in Africa, southwest Asia and India (see Fig.  5 1). Psix asper is an Ethiopian species, known only from Uganda; in some cladograms it appears as the sister species of the Zacunatus group. The earlier-derived species occur in the Australian and eastern Oriental realms. Psix lacunatus bridges these two groups: it is the basal branch of its species group and connects the generally western distribution of its relatives with the more plesiomorphic eastern species. As discussed above, Psik tunetanus has an unusual distribution for the genus in that it extends to the New World. We believe this may be a result of accidental introduction by man. There remain too many large unsampled areas to make any other, more detailed inferences about the evolution and zoogeography of Psix.
The position of the genus Psix within the subfamily Telenominae is uncertain. As we have already mentioned, species such as P.con$uus have many characters that are ptesiomorphic for the subfamily as a whole. Indeed, the striking feature of the genus, the striate frons, is a very common character in the Scelioninae and Teleasinae. This suggests an early derivation of the genus from the common ancestor of the Telenorninae.
Another possibility is that Psix is a specialized exgroup of Trissolcus. Resolution of this general question awaits a better understanding of other relatively plesiomorphic telenomine groups, particularly those now classified within Trissolcus. The concentration of plesiomorphic species of Psix in Australia and southeast Asia suggests that clues may be found in that part of the world.