Updating the taxonomy of the bee genus Megalopta (Hymenoptera: Apidae, Augochlorini) including revision of the Brazilian species

Megalopta (Smith 1853) is a nocturnal and/or crepuscular bee genus, with Neotropical distribution. The present work presents a taxonomic revision of Megalopta with emphasis on the Brazilian species through diagnosis and description of species and an identification key for most species that occur in South and Central America, with figures and distribution maps. Moreover eight new species are described: Megalopta guarani sp. n, M. mura sp. n, M. piraha sp. n, M. munduruku sp. n, M. yanomami sp. n, M. xavante sp. n, M. mapinguari sp. n. and Megalopta karitiana sp. n. Sex association for the male of M. chaperi (Vachal, 1904) is presented. Also we present taxonomical notes of valid species, with designation of lectotypes, new synonymies and checklist of valid species. Now, 32 valid species are recognized for the genus, with 19 in the Brazilian fauna. The present work enables correct identification of the species, which should facilitate further studies with Megalopta. http://zoobank.org/urn:lsid:zoobank.org:pub:6DB510C5-259A-4A66-AB36-7745AD4F53E9


Introduction
Megalopta is a speciose genus within the bee tribe Augochlorini, with distribution from southern Brazil (state of Santa Catarina) to the state of Sinaloa, in Mexico (Michener 2007;. Currently, the genus has 30 valid species, most of them inhabiting the Amazon basin (Moure 2007;Santos and Silveira 2009;Engel 2011). Dating based on molecular analyses estimates that the genus diversification probably started in the Tertiary, with a range between 15 and 30 mya (Danforth et al. 2004;Tierney et al. 2012).
These relatively large halictine bees, with body length varying between 9 and 20 mm, are conspicuous elements of the Neotropical wet forests. The species of Megalopta are well known for being obligate dim-light bees, with a specialized visual system that allows them to forage in twilight conditions, unlike diurnal bees (Greiner Diagnosis Megalopta differs from other augochlorines, including Xenochlora, by the large ocelli and the closely packed series of hamuli in the hind wing (Engel 2000;Michener 2007), as well as in the morphology of the male S3-S5 (Santos and Melo 2013). Megalopta and Xenochlora differ from most augochlorines for their non-metallic, pale brown metasoma. A pale metasoma is present in Megaloptidia Cockerell, Megommation Moure, and some species of Megaloptina Eickwort, but these genera have a very slender proboscis, with the prementum 10 to over 20× as long as broad, and except for Megaloptina, also a serrate inner metatibial spur, while in Megalopta and Xenochlora the proboscis is not so slender, with the prementum about 4-8× as long as broad, and the inner metatibial spur is pectinate.
Three main lineages are recognized in the genus, the first one formed by the cleptoparasitic species, corresponding to the subgenus Noctoraptor, and treated here as the byrony group, the second one formed by the species in which the males have a conspicuous large process covered with velvety pilosity in the posterior upper margin of the metepisternum, and the last lineage comprises those species lacking a welldeveloped metepisternal process (Santos and Melo, unpublished data). The species of the second and third lineages can be further subdivided in four species groups: aegis, amoena, yanomami and sodalis. A subgeneric classification is not adopted here because the available name Megaloptella applies only to the amoena species group and Tmetocoelia has been shown to form a paraphyletic assemblage (Santos and Melo, unpublished data).

Identification key to the species of Megalopta from Brazil
This key includes species that occur in other South American countries (Bolivia, Ecuador, French Guiana, Guyana, Nicaragua, Peru, Suriname, Trinidad and Tobago, and Venezuela) and in Central America.
-Basal area of metapostnotum without defined external sulcus delimiting the longitudinal rugulosities, integument light green ( Figure 4B); metanotum often densely punctured (< 1 pd) ( Figure    3 (2). Glabrous basal portion of F6-F11 raised in relation to remainder of flagellomere surface ( Figure 8D); pilosity of metanotum restricted to two-thirds of disc, not obscuring the integument in oblique view ( Figure 6C); basal area of metapostnotum entirely metallic green or sometimes reddish brown medially ( Figure 6C) Figure 8E); metanotum often with very dense pilosity covering entire disc and obscuring the integument in oblique view ( Figure 6D, F); basal area of metapostnotum reddish brown, orangish or reddish brown with metallic green, never entirely metallic green ( Figure 6D, F   -Inner orbit of eye strongly angled ( Figure 10C); ocellocular distance shorter than F1 length; F2 about as long as F3; dorsal surface of flagellomeres strongly depressed ( Figure 10D)  -Integument mostly dark brown to black ( Figure 12B

Diagnosis
The aegis species group includes M. aegis, M. aeneicollis, M. nitidicollis and M. sulciventris. Its species can be identified by the following characters: posterior margin of basal area of metapostnotum arcuate, gradually curved toward the metanotum laterally, the longitudinal rugulosities sometimes numerous and present laterally ( Figure 1D); upper frons conspicuously convex, strongly declivous toward sulcus around median ocellus ( Figure 1E); male with glabrous basal portion of F6-F11 expanded ( Figure 8D, E); posterior upper margin of metepisternum modified into a conspicuously large process covered with velvety pilosity in both sexes, its diameter at least 0.5× the tegula length ( Figure 1A); basal area of metapostnotum laterally with rugulose surface, the posterior margin arcuate, gradually curved towards the anterior margin laterally ( Figure 1D, 2B-D, 6C-6F); 1st and 2nd tarsomere of foreleg with longest simple setae longer than summed length of the three apical tarsomeres and T1 with contiguous punctation. Examined material (374♀, 49♂). See Appendix 2.

Diagnosis
The female differs from that of M. nitidicollis by the weak longitudinal rugulosities along its entire surface of the basal area of metapostnotum; from M. aeneicollis by reddish brown basal area of metapostnotum and by the imbricated rugulosities in its lateral surface ( Figure 2D); from M. sulciventris by metanotum with dense short plumose pilosity present on its entire surface and by colour of integument of basal area of metapostnotum, entirely reddish brown or reddish brown in the centre with green tints laterally ( Figure 2D). The male differs from that of M. sulciventris by the F6-F11 basally with glabrous area levelled to remainder of flagellomere surface ( Figure 8E), metanotum with very dense pilosity covering entire disc, obscuring the integument in dorsal view, and by reddish brown basal area of metapostnotum; from M. aeneicollis and M. nitidicollis by basal area of metapostnotum with strongly impressed longitudinal rugulosities along its entire surface ( Figure 6E).

Description
Female.
(2) Labral elevation with lateral surface slightly raised in relation to central portion.

Diagnosis
The female differs from that of M. nitidicollis by the evenly strongly impressed longitudinal rugulosities along entire surface of the basal area of metapostnotum ( Figure 2C); from M. aegis and M. sulciventris by the basal area of metapostnotum often orangish, entirely finely rugulose, stronger rugulosities rectilinear and long along entire surface ( Figure 2C). The male is distinguished from that of M. sulciventris by the F6-F11 basally with glabrous area levelled to remainder of flagellomere surface, metanotum with very dense pilosity covering entire disc, obscuring the integument in dorsal view, and by basal area of metapostnotum light orangish brown ( Figure 6D); from M. aegis and M. sulciventris by the basal area of metapostnotum entirely finely rugulose, and with its posterior margin slightly raised ( Figure 6D).

Description
Female.
(2) Labral elevation with lateral surface slightly raised in relation to central portion.

Type material
There is one female and one male syntype in the ZMB collection.

Diagnosis
The female differs from those of M. aegis, M. aeneicollis and M. sulciventris by the weakly impressed longitudinal rugulosities in the central portion of the basal area of metapostnotum, in contrast with the strong rugulosities laterally, and by the integument of the basal area often reddish brown on basal half and metallic green on apical half ( Figure 2B). The male is distinguished from that of M. sulciventris by glabrous basal portion of F6-F11 levelled to remainder of flagellomere surface; metanotum with very dense pilosity covering entire disc, obscuring the integument in dorsal view, and by the basal area of metapostnotum reddish brown on basal half and metallic green apically ( Figure 6F); from M. aeneicollis by basal area of metapostnotum in posterior margin forming a carina; from M. aegis by basal area of metapostnotum lacking longitudinal rugulosities or only with a few weak rugulosities in its mid portion ( Figure 6F). Additional examined material (93♀, 14♂). See Appendix 2.

Diagnosis
The female differs from that of M. nitidicollis by the weakly impressed longitudinal rugulosities along entire basal area of metapostnotum ( Figure 1D); from M. aeneicollis by the metallic green basal area of metapostnotum and by its imbricated longitudinal rugulosities towards lateral portions ( Figure 1D); from M. aegis by the metanotum sometimes with pilosity short and plumose, present only on two-thirds of disc, not obscuring the integument in oblique view ( Figure 1D) and basal area of metapostnotum metallic green and with strongly imbricated longitudinal rugulosities ( Figure 1D). The male differ from those of M. aegis, M. aeneicollis and M. nitidicollis by the glabrous basal portion of F6-F11 raised in relation to remainder of flagellomere surface ( Figure 8D); metanotum pilosity present only in two-thirds of disc and not obscuring the integument in dorsal view ( Figure 6C); basal area of metapostnotum entirely metallic green or sometimes reddish brown medially ( Figure 6C).

Description
Female.
(2) Labral elevation with lateral surface slightly raised in relation to central portion.

Diagnosis
The amoena species group includes M. amoena, M. chaperi, M. guimaraesi and M. mura sp. n. Its species can be recognized by the following characters: posterior upper margin of metepisternum modified into a conspicuously large process covered with velvety pilosity, its diameter at least 0.75× the tegula length (except in the female of M. amoena); male E3 centrally in the apex with sinuous notch adjacent to expanded area of sternum ( Figure 8A-C).

Diagnosis
The female differs from those of M. chaperi, M. guimaraesi and M. mura sp. n. by posterior upper margin of metepisternum unmodified, lacking a velvety process ( Figure 5D) and by the smooth basal area of metapostnotum lacking rugulosities ( Figure 2F). The male is distinguished from that of M. chaperi by the metanotum in dorsal view with sparse pilosity and by the short basal area of metapostnotum, its length at least 0.8× that of metanotum ( Figure 7C); from M. guimaraesi and M. mura sp. n. by F6-F11 about as wide as basal flagellomeres ( Figure 8F), central area of basal area of metapostnotum without longitudinal rugulosities ( Figure 7C), S3 without longitudinal carina ( Figure 8B) and S4 basally with pilosity, its apical margin slightly notched laterally ( Figure 9B).

Description
(1) Mandible bidentate and with supplementary teeth. (2) Figure 8B). (22) S4 with medial protruding process, profile of process triangular in lateral view; basal portion with dense short pilosity; posterolateral margin sinuous, the apical margin without a set of dense hairs ( Figure 9B).

Comments
Several females exhibit metallic green highlights in the mesoscutum and some males have a metallic green basal area of the metapostnotum.

Diagnosis
This species differs from M. amoena, M. guimaraesi and M. mura sp. n. by the very short basal area of metapostnotum, its length about one-third as long as metanotum ( Figure 2E). Its males are also distinguished by the metanotum in dorsal view with dense pilosity ( Figure 7B).  Figure 8A).

Comments
In the specimens from Uiramutã and Amajari, in Roraima, the basal and central areas of the clypeus have a smooth surface between punctures.

Diagnosis
The female differs from that of M. amoena by possessing in posterior upper margin of metepisternum a conspicuously large process covered with velvety pilosity; from M. chaperi by the longer basal area of metapostnotum, its length always longer than onethird of metanotum length ( Figure 1F); from M. mura sp. n. by the mesoscutum, adjacent to parapsidial line, densely punctured (< 1 pd), punctuation sparser in direction to mesoscutal lip (≥ 1 pd) ( Figure 3B), scutellum with posterior margin levelled to anterior margin of metanotum ( Figure 3C), and by basal area of metapostnotum uniformly metallic green ( Figure 1F). The male differs from that of M. chaperi by the longer basal area of metapostnotum, its length always longer than onethird of metanotum length and by sparse pilosity in metanotum ( Figure 7D); from M. amoena by F6-F11 wider than remaining flagellomeres ( Figure 9A), basal area of metapostnotum with longitudinal rugulosities in mid portion ( Figure 7D), S3 with a weakly impressed longitudinal sulcus, S4 lacking pilosity basally, its apical margin strongly notched laterally; from M. mura sp. n. by the sparse punctures (≥ 1 pd) in mesoscutum adjacent to parapsidial line.  (Figure 2A). (7) Ocellocular distance smaller than the F1 length. (8) Mesoscutum adjacent to the parapsidial line densely punctured (< 1 pd), punctation sparser in direction to mesoscutal lip (≥ 1 pd) ( Figure 3B). (9) Scutellum with posterior margin levelled in relation to anterior margin of metanotum ( Figure  3C). (10) Metanotum with integument, in oblique view, not hidden by short plumose pilosity. (11) Basal area of metapostnotum* sometimes metallic green, its length up to 0.7× that of metanotum, with few slightly impressed longitudinal rugulosities ( Figure  1F). (12) Mesepisternum with contiguous punctation. (13) Metepisternum with dense pilosity, integument not visible through pilosity, posterior upper margin modified into a conspicuously large process covered with velvety pilosity, its diameter at least 0.75× the tegula length. (14)

Comments
Specimens from eastern Brazil exhibit blackish integument, while those from central Brazil have a metallic green integument. However, one female from Camacan, Bahia, has a mostly black integument mixed green tints and one male from Rio de Janeiro is metallic green.  Figure 15B).
Megalopta mura sp. n. (Figures 1B, 3A, 3D-E, 7E-F, 8C, 15B) Diagnosis Different from M. chaperi by the length of basal area of metapostnotum in relation to metanotum length, its length never a third, and usually a half of metanotum length ( Figure 3A). The female differs from M. amoena by presence in posterior upper margin of metepisternum of a conspicuously large process covered with velvety pilosity ( Figure 1B) and the male by the F6-F11 wider than remaining flagellomeres; basal area of metapostnotum with longitudinal rugulosities present in central area ( Figure 7E); S3 longitudinal sulcus slightly impressed ( Figure 8C); S4 basally lacking pilosity, the apical margin strongly notched laterally ( Figure 8C). Both sexes are distinguished from M. guimaraesi by the mesoscutum adjacent to parapsidial line with contiguous punctation, punctation becoming sparser towards the mesoscutal lip (< 1 pd) ( Figure 3D); also the female differs by the scutellum with posterior margin raised in relation to anterior margin of metanotum ( Figure 3E); basal area of metapostnotum often brownish in the centre and metallic green in the sides ( Figures 3A, 7E).  Figure 3E). (10) Metanotum with integument, in oblique view, not hidden by short plumose pilosity. (11) Basal area of metapostnotum reddish brown with green metallic tints laterally, its length up to 0.6× that of metanotum, with longer longitudinal rugulosities restricted to central area ( Figure 3A). (12) Mesepisternum with contiguous punctation. (13) Metepisternum with dense pilosity, integument not visible through pilosity; posterior upper margin modified into a conspicuously large process covered with velvety pilosity, its diameter at least 0.75× the tegula length ( Figure 1B). (14) T1 with dorsal surface of disc sparsely punctured (≥ 1 pd), posterior marginal zone smooth between punctures. Male. (15) Scape with diameter gradually enlarging toward the apex. (16) Flagellum reddish brown; F1-F11 differing in diameter, F6-F11 wider than remaining flagellomeres; F2 about as long as F3; F6-F11, in anterior view, with the anterior and posterior margins depressed, in posterior view, basally with basal glabrous area at same level of remaining surface. (17) Metanotum with integument, in dorsal view, not hidden by short plumose pilosity ( Figure 7E). (18) Basal area of metapostnotum metallic green, its length up to 0.5× that of metanotum, longitudinal rugulosities restricted to central area ( Figure 7E). (19) Metepisternum with very dense pilosity, the integument not visible through pilosity; posterior upper margin modified into a conspicuously large process densely covered with velvety pilosity, its diameter at least 0.75× the tegula length ( Figure 7F). (20) 1st and 2nd tarsomeres of foreleg with longest simple setae shorter than summed length of the three apical tarsomeres. (21) S3 with longitudinal sulcus, slightly impressed posterolateral margin strongly notched ( Figure 8C). (22) S4 with medial protruding process, profile of process triangular in lateral view, basal portion glabrous, posterolateral margin notched, notch not extending to basal half of sclerite ( Figure 8C).

Comments
The female from Acrelândia, Acre, was collected in a euglossine trap baited with benzil acetate.  Figure 15B).

Etymology
The specific epithet honours the 'Mura', the name for an ethnic group of South American natives, used here as a noun in apposition. They are known for navigating along extensive areas in the rivers Amazonas, Madeira and Purus. In their long history of contact with European settlers, this group has been repeatedly stigmatized and suffered from massacres, as well as demographic, linguistic and cultural losses. Today, they live at indigenous reserves and urban centres in northern Brazil (Amoroso 2009).

Diagnosis
The yanomami species group includes only two species, both described here as new, M. piraha sp. n. and M. yanomami sp. n. They can be identified by the following characters: posterior upper margin of metepisternum unmodified, lacking a velvety process; basal areal of metapostnotum smooth laterally and with a few longitudinal rugulosities restricted to mid portion. Megalopta piraha sp. n. is more widely distributed in the Amazon basin, while M. yanomami sp. n. is known only from Roraima and a single locality in eastern Pará ( Figure 15C).

Diagnosis
It differs from M. yanomami sp. n. by the basal area of metapostnotum without defined external sulcus delimiting the longitudinal rugulosities, the integument light green ( Figure 4B, 12E); the male is also distinguished by the scape enlarged gradually in direction to the apex ( Figure 13E) and by flagellomeres without depressed and glabrous area ( Figure 10D).   Figure 15C).

Etymology
The specific epithet honours the 'Pirahã' or 'Mura-Pirahã', the name for an ethnic group of South American natives, descendents of the 'Mura', used here as a noun in apposition. The Pirahã inhabit a tract of lands traversed by the Marmelos river and almost the entire length of the Maici river, located in the municipality of Humaitá, in Amazonas, northern Brazil (Gonçalves 2000).

Etymology
The specific epithet honours the 'Yanomami', the name for an ethnic group of South American natives, used here as a noun in apposition. The 'Yanomami' comprise a society of hunter-agriculturists of the tropical rainforest of northern Amazonia, whose contact with non-indigenous society over most of their territory has been relatively recent. Their territory covers an area of approximately 192,000 km 2 , located on both sides of the border between Brazil and Venezuela, in the Orinoco-Amazon interfluvial region (affluents of the right shore of the Rio Branco and left shore of the Rio Negro). The total population of the 'Yanomami' in Brazil and Venezuela is today estimated to be around 26,000 people (Albert 1999).

Diagnosis
The byroni group includes M. atlantica Santos & Silveira, M. guarani sp. n., M. xavante sp. n., M. mapinguari sp. n., M. purpurata Smith, M. karitiana sp. n. and additional species previously placed in the subgenus Megalopta (Noctoraptor) Engel, Brooks and Yanega. It is distinguished from other species groups by the ocellocular distance equal to length of F1 and by the sparsely punctured mesoscutum posteriorly to mesoscutal lip (≥ 1 pd). The female differs from those of other groups by lacking the mandibular subapical and supplementary teeth and the basal macula in the inner surface of the mandible. The male is characterized by the F2 as wide as about twothirds of F3, dorsal surface of flagellomeres flattened to slightly depressed and by the protruding process of S4, in lateral view, digitiform or triangular and short. It is shown here that this group also contains species with a metallic green integument, differing from the previously described dark brown non-metallic species.
Bees in this group are rarely collected and most species are known from single specimens or small series. All known females in the byroni group have a morphology associated with non nest-making, parasitic behaviour. Biani and Wcislo (2007), in their work on M. byroni, consider that this group might behave as obligatory cleptoparasites or social parasites. Taking into consideration that female morphology in this group is more similar to that of macrocephalic females of nest-making species, it is more plausible to believe that they behave as social parasites. Macrocephalic females exhibit dominant queen-like behaviour over the non macrocephalic subordinate females.

Diagnosis
The male differs from those of M. atlantica, M. purpurata, M. xavante sp. n., and M. mapinguari sp. n. by the shape of the medial protruding process of S4, being short and having a triangular profile in lateral view ( Figure 10E); from M. karitiana sp. n. by the colour of the integument, metallic green in the head and mesosoma with coppery tints (Figures 9C, 10F) and reddish brown on metasoma.

Etymology
The specific epithet honours the 'Guarani', the name for an ethnic group of natives used here as a noun in apposition. Since the mid-1920s, for the Guarani subgroup Kaiowa, there has been a continuous process of expropriation of Guarani lands, which are constantly threatened by farmers (Almeida and Mura 2003).

Diagnosis
The male differs from those of M. atlantica, M. purpurata, M. xavante sp. n., and M. mapinguari sp. n. by the minute medial protruding process of S4, with a triangular profile in lateral view; from M. guarani sp. n. by the dark brown integument with metallic green reflections, and the dark brown metasoma with purple tints.   Figure 15D).

Etymology
The specific epithet honours the 'Karitiana', the name for an ethnic group of natives, used here as a noun in apposition. The 'Karitiana' experienced a brutal demographic decline after contact with the whites. Indeed, the anthropologist Darcy Ribeiro considered them extinct in 1957, however the current population numbers around 320 individuals (Storto and Velden 2005).

Comments
The collecting date of the type specimen is unknown. The species can be easily recognized by intense metallic green reflections, sometimes mixed with black tints in integument, except for predominantly blackish metasoma.

Etymology
The specific epithet honours the 'Mapinguari', used here as a noun in apposition. The 'Mapinguari', a Brazilian folklore character, is popularly known as a monster that lives in the Amazon Rainforest.

Diagnosis
The male differs from those of M. guarani sp. n. and M. karitiana sp. n. by the digitiform medial protruding process of S4, in lateral view; from M. mapinguari sp. n and M. xavante sp. n. by the mesosoma homogeneously blackish ( Figures 11F, 12C); also distinguished from M. mapinguari by medial protruding process of S4 lacking setae in the apex; from M. atlantica by the absence of rugulosities in basal area of metapostnotum ( Figure 12C).

Comments
The type was not examined directly, but through photographs obtained from the British Museum (BMNH). Its inclusion in the byroni species group was based on the following features: body coloration without metallic green reflections and S4 in basal area with a digitiform medial protruding process. Some characteristics of this species were extracted from Moure's (1958) redescription.

Etymology
The specific epithet honours the 'Xavante', the name for an ethnic group of natives, used here as a noun in apposition. The Xavantes live in nine indigenous areas which are part of the territory they traditionally occupied for at least 180 years, in eastern Mato Grosso. The region where they live has suffered the environmental impact of extensive cattle ranching since the 1960s, an impact which is almost certainly irreversible. From the 1980s the impact has been intensified by the spread of giant grain farms, especially soybeans produced for export (Graham 2008).

Diagnosis
The sodalis species group includes: M. cuprea, M. munduruku sp. n. and M. sodalis. Members of this species group can be recognized by having the mid portion of the basal area of the metapostnotum with depressed triangular area with longitudinal rugulosities branching from central rugulosities, or with transverse depression in M. munduruku sp. n., and by having the posterior upper margin of the metepisternum unmodified, lacking a velvety process in both sexes. Furthermore, this species group exhibits a large amount of intraspecific variation in the shape of the basal elevation of the labrum and in the basal area of the metapostnotum.
M. cuprea occurs in Bolivia and northern Brazil ( Figure 16A), while M. munduruku sp. n. is found only in northern Brazil ( Figure 16B) and M. sodalis is widely distributed ( Figure 16C).

Diagnosis
The female differs from that of M. munduruku sp. n. by mid depression extending to posterior margin in basal area of metapostnotum ( Figure 4D) and the male, by basal area of metapostnotum with longer and strongly impressed longitudinal rugulosities ( Figure 13A); both sexes can be distinguished from M. sodalis by head and thorax mostly dark brown, lacking metallic reflections.

Comments
All studied specimens were from Bolivia. The only record of this species in Brazil was published by Friese (1923:3), based on a female from 'Manaos'. However, no additional specimens from Brazil have been found during this study and Friese (1926:124) does not include the Brazilian record in his treatment of M. cuprea.

Diagnosis
The female differs from those of M. cuprea and M. sodalis by basal area of metapostnotum with mid depression restricted to anterior half, not extending to posterior margin ( Figure 4C) and the male, by basal area of metapostnotum with shorter and weakly impressed longitudinal rugulosities ( Figure 12F). Distribution BRAZIL. Amazonas: Fonte Boa, Manaus, Novo Airão. Pará: Belterra ( Figure 16B).

Etymology
The specific epithet honours the 'Munduruku', the name for an ethnic group of natives used here as a noun in apposition. Historically a people with a warrior tradition, the Munduruku culturally dominated the region of the valley of the Tapajós River, Brazil. Today, the wars they wage are to guarantee the integrity of their territory, threatened by pressures from the illegal activities of gold-panning, hydroelectric projects, and the construction of a great waterway on the Tapajós river (Ramos 2003 Examined material (525♀, 111♂). See Appendix 2.

Journal of Natural History 631
Diagnosis This species differs from M. cuprea only by the metallic green integument; from females of M. munduruku sp. n. by basal area of metapostnotum with mid depression extending to posterior margin ( Figure 4E), and from males, by longer and strongly impressed longitudinal rugulosities in the basal area of metapostnotum ( Figure 13C).

Description
Female.
(2) Labral elevation* with flattened, slightly depressed or with lateral surface strongly raised in relation to central portion.

Comments
One specimen from Itu, São Paulo, and another from Nova Lima, Minas Gerais , exhibit a dark body coloration. The specimens from Mucugê, Bahia and another from Itatiaia, Rio de Janeiro, were collected respectively in Cambessedesia wurdackii (Melastomataceae) and Bauhinia forficata (Fabaceae). This is the largest species of Megalopta, with some females reaching almost 20 cm in body length, but many specimens exhibit smaller body size. These smaller specimens may be the result of parasitism by Fiebrigella spp.
(Diptera: Chloropidae), whose larvae consume pollen of brood cells and are known to reduce the body size of adult Megalopta bees (Smith et al. 2008).
Information on nests of this species was published by Sakagami and Moure (1967). Furthermore, specimens have been attracted by eugenol and methyl salicilate.
The present synonymy is based on the morphology of both sexes; many characters exhibit intraspecific variation, such as the shape of the labral elevation, length of metapostnotum, tergal punctation and body size. Some individuals show purple tints in the basal area of metapostnotum adjacent to the rugulosities. It is possible that this species is a junior synonym of M. sodalis.

Comments
This species is most similar to M. sodalis, but differs from that species mainly in the bluish integumental color. Synonymy here would be premature without examining more material from Bolivia.