A revised key to the Neotropical cleptoparasitic anthidiine genera (Hymenoptera, Megachilinae) with notes and description of the male of Rhynostelis Moure & Urban

Abstract Rhynostelis Moure & Urban is a monotypic cleptoparasitic neotropical anthidiine genus currently known from two females. Herein, we describe and illustrate for the first time the male and its genitalia and it is confirmed that Rhynostelis parasitizes nests of Eufriesea. An identification key to the genera of cleptoparasitic anthidiine from the Neotropical region is also presented.


Introduction
Cleptoparasitism is a common behavior among species of Anthidiini and presumably evolved multiple times within the tribe (Gonzalez et al. 2012). This condition is currently known in eleven genera worldwide, seven of which occur in the neotropical region, Austrostelis Michener & Griswold, 1994;Dolichostelis Parker & Bohart, 1979;Heterostelis Timberlake, 1941; Hoplostelis Dominique, 1898; Rhynostelis Moure & Urban, 1995;Stelis Panzer, 1806; and the recently described Melostelis Urban, 2011, which is known from a single female from the Amazon (Michener 2007, Moure & Urban, 2007. In the classification proposed by Michener (2007), Austrostelis, Hoplostelis and Stelis are treated as genera, with remaining taxa treated as subgenera. In this contribution, all taxa are treated at the generic level, according to the classification of Urban and Moure (2007).
Rhynostelis consists of a single species, R. multiplicata (Smith, 1879), which is known from two female specimens collected on the State of Amazonas, Brazil. Herein, we present an updated diagnosis of Rhynostelis, describe and illustrate the male of R. multiplicata and, based on two specimens collected from a trap-nest, we record the orchid bee Eufriesea laniventris (Ducke, 1902) as its host. A key to all neotropical cleptoparasitic anthidiine genera is also provide.

Material and methods
Morphological terminology follows Michener (2007) and that for mandibles Michener and Fraser (1978). Measurements are given in millimeters and were taken using an ocular micrometer on a stereoscopic microscope Leica MZ125. Total length was measured in lateral view, from the head to the apex of metasoma; length of forewing was measured at the anterior margin, from the costal sclerite to the wing apex. The illustrations were obtained with a Leica DFC 500 digital camera attached to the stereoscopic microscope Leica MZ 16 and combined with the software AUTO-MONTAGE PRO. All material used in this study is deposited in the Coleção Entomológica Pe. Jesus Santiago Moure, Universidade Federal do Paraná, Curitiba, Brazil (DZUP). Description. Mandibles with distal margin almost straight, only with apical tooth elongated; upper distal angle slightly marked, condylar carina elevated and strongly laminated, slightly wider at base (Fig. 2). Clypeus protuberant with median basal tubercle elongated, extended in low irregular carina in basal half, apex depressed without projections, not exceeding labrum, covered by many long hairs. Labrum weakly bilobed near clypeal base. Supraclypeal area with wide, somewhat flat median carina; frons with long, well marked carina. Juxtantennal carina laminated, ventrally short, not arising at base of antennal sockets and extending upward (Fig. 1). Scutum and scutellum bigibbous; axillae gibbous; base of propodeum with irregular foveae (Fig. 3, 5). Omaulus lamellate, almost extending ventrally; mesepisternum with gibbous area near mesocoxal cavity. Fore and middle tibiae with midapical spine on outer surface (Fig. 15); arolia present. Fifth and sixth terga with transverse, median low carina; sixth tergum with apical projection at middle; distal tergum slightly emarginated at apex (Fig. 6). Second sternum enlarged, with apex weakly emarginated at middle, with long pilosity at apex; third to fifth sterna with dense apical pilosity, laterally with longer and curved hairs; sixth sternum with distal margin almost straight, with large, angled, laminar, lateral projections subapically.
Comments. Moure and Urban (1995) mentioned that the base of the propodeum in Rhynostelis lacks foveae. Michener (2007), also pointed out this feature as one of the characteristics that separates Rhynostelis from Hoplostelis. However, a reexamination of Rhynostelis specimens revealed the presence of irregular fovea in the base of its propodeum, which are difficult to see due the shiny yellow integument. Michener (2007) considered Rhynostelis as a subgenus of Hoplostelis and in his key, the male agrees with the female by the characters he listed, except for the absence of foveae in the base of propodeum, as commented above. The male of Hoplostelis further differs from Rhynostelis by the following combination of characters: three strong mandibular teeth and two basal depressions near the articulation of the head; omaulus carinate only in the dorsal one-half or one-third; sixth sternum with narrow lateral projections and without gibbous mesosoma. Diagnosis. Integument black, with wide yellow areas in both sexes. Scutum with a large, reverse U-shaped macula; scutellum almost totally yellow; axillae yellow and all terga with yellow bands (Figs 3, 4). Male and female with protuberant clypeus.

Rhynostelis multiplicata
Male description. Approximate body length 13.29; forewing length 10.45; head width 4.02; head length 3.67; eye length 2.55. Head integument yellow except: distal margin of mandible and apical tooth black; labrum blackened; frons black, bands above superior margin of antennal sockets extending to vertex, including ocelli and finely attached with black spot above compound eyes. Antennae with ventral face of pedicel darkish yellow, remaining segments light brown; dorsal face with scape and pedicel light brown and flagellum amber (Figs 1, 2). Pronotal lobe yellow; scutum black with large reverse U-shaped yellow maculae; scutellum with on yellow gibbous area joined medially by fine yellow band; axillae yellow; metanotum brown and propodeum yellow. Mesepisternum and metepisternum yellow; mesepisternum with discal black spot, metepisternum with ventral area black. Tegula amber and wing membrane brown. Legs almost totally yellow; middle tibiae with internal darkish area and hind tibiae with large internal darkish area (Figs 3, 4, 5). Terga black; basal tergum with yellow band slightly angled at middle; second to fourth with large yellow band, slightly narrower and slightly interrupted medially; fifth tergum with yellow band emarginated at middle on posterior margin; sixth tergum with yellow band, wider medially; distal tergum with subapical yellow band and blackish margin (Fig. 6). Two basal sterna yellow, with large translucent margin; third to fifth yellow with black infumated area on apical half; sixth sternum with large median black apical spot.
Pubescence. Light yellow with predominantly short hairs (less than ocellus diameter). Pilosity longer and denser among ocelli, above antennal sockets and clypeus apex. Hairs of mesepisternum little longer than mesoscutum, curved on scutellum and propodeum. Fore leg with coxa and trochanter covered by dense pilosity. Third to fifth sterna with apical dense and long slight curved hairs.
of mesepisternum with larger and sparser punctures; distance between punctures at least half width a puncture diameter. Punctures of terga fine and shallow; punctures on yellow bands larger and sparser than those on black areas.
Remarks on the female from Pará. Approximate body length 16.13; forewing length 12.38; head width 4.90; length head 4.16, eye length 3.18. Integument predominantly yellow. The female differs from the male as follows: black maculae on vertex and frons larger than in male. All terga with yellow bands; basal tergum with complete band; second and third terga with bands slightly interrupted at middle; fourth tergum with band interrupted anteriorly only at middle, fifth tergum with band interrupted only posteriorly at middle; sixth tergum with subapical band and blackish margin. All sterna yellow; distal sternum with medioapical spot and black margin. The female collected in Manaus is a little smaller than the female from Belém and the integument of the head is darker and with irregular macula. Such differences in color might be caused by some chemical product used during collection or preservation.
Host records. Urban & Moure (1995) commented that one female of R. multiplicata emerged from a test-tube placed on a termite nest where an orchid bee was previously seen (possible Eufrisea pulchra (Smith, 1854)). However, the record of the host was never confirmed. The specimens from Belém studied herein emerged from one nest of Eufriesea laniventris (Ducke, 1902), (DZUP), according the identification of Dr. Gabriel A. R. Melo. Thus, the cleptoparasitism of R. multiplicata on orchid bees of the genus Eufriesea is confirmed.  (Fig. 3, 4). Integument with fine to moderate-sized punctures; pilosity among ocelli longer than in remaining areas of head (Fig. 12)