Calosota albipalpus

Description. FEMALE (Figs 19, 38). HOLOTYPE: length 2.3 mm. Color. Head (Fig. 9) with frontovertex and scrobal depression dark brown with slight bluish-green lusters under some angles of light, but smooth part of parascrobal region yellowish to reddish-coppery and interantennal region and lower face distinctly greenish-blue to purple under different angles of light. Maxillary and labial palpi white (Fig. 9). Antenna dark brown except scape and pedicel dorsally with slight bluish-green lusters under some angles of light. Tegula dark. Mesoscutum (Fig. 19) largely dark similar to frontovertex, but under some angles of light posterior region of larger meshlike-reticulations with coppery luster and anteriorly with greenish-blue to bluish-purple lusters; scutellar-axillar complex similar in color to mesoscutum posteriorly. Acropleuron variably reddish-violaceous to bluish-green under different angles of light. Legs (Fig. 38) with femur and tibia of front leg extensively dark brown, but trochanter, trochantellus, knee, about apical quarter of tibia, and tarsus yellowish-white; middle leg yellowish-white beyond coxa except femur with short subapical dark brown band (reduced on dorsal surface) and tibia with short subbasal dark brown band opposite femoral band when appressed to femur; hind leg yellowish beyond coxa except about basal half of femur brown and dorsal margin of tibia with short subbasal brownish region. Fore wing hyaline; setae uniformly brown. Gaster mostly with reddish-coppery lusters dorsomedially, but more yellowish-green paramedially to greenish-blue laterally (Fig. 38), except penultimate tergum reddish-coppery basally to more yellowish-green apically and syntergum and Gt1 basally bluish-purple. Structure/setation. Head in dorsal view about 1.66× as wide as long, with IOD about 0.42× head width; IOD: MPOD: OOL: POL: LOL = 35: 7: 5: 14: 9; in frontal view about 1.3× as wide as high, with about middle of torulus at level of lower orbits; malar space about 0.55× eye height. Head (Figs 9, 66) with frontovertex and upper parascrobal region finely coriaceous; scrobal depression, lower parascrobal region, and paraclypeal region along inner orbit almost or completely smooth and shiny; clypeal region and interantennal region meshlike coriaceous, but lower parascrobal region near scrobal depression and most of paraclypeal region obliquely coriaceous-alutaceous. Head with brownish setae on frontovertex but more whitish setae on interantennal region and lower face. Antenna (Fig. 38) with flagellum clavate; length of flagellum + pedicel about 1.4× head width; scape: pedicel: fu1–fu8: clava = 36(9): 14(6): 4(4), 10(5), 10(5), 10(5), 10(6), 9(7), 9(7), 9(8): 35(12). Mesoscutum with inclined anterior surface and lateral lobes meshlike coriaceous, but dorsal surface anterior to scutellar-axillar complex very shallowly meshlike reticulate, the reticulations large and flat-bottomed, and with sparse, brownish setae; notauli, anteroadmedian lines and parapsidal lines all obscure. Axillae elongate-slender, separated by about 4× own width (Fig. 76). Scutellum low convex, only slightly longer than wide; elongate strigose-reticulate (Fig. 76); with inconspicuous dark setae. Mesopleuron with reduced lower mesepimeron, but narrow vertical surface under convex acropleuron above base of mesocoxa with 2 setae projecting between bases of meso- and metacoxae (Fig. 81); acropleuron without distinct miscrosculptured region, very finely, obliquely coriaceous-alutaceous anteriorly and much more elongate, longitudinally alutaceous-aciculate posteriorly. Fore wing with cc: mv: stv: pmv = 54: 53: 10: 12; basal cell entirely setose; cubital area bare, including along posterior margin to about level of basal fold; disc with oblique bare band behind base of marginal vein (distinct only for left wing) separated from marginal vein and from posteriorly widened bare region along parastigma and basal fold, the latter bare area continuous with cubital area because of short, bare region of mediocubital fold beyond basal fold. Metacoxa setose along dorsal, ventral and basal margins, and outer surface with a few scattered setae within about basal third. Propodeum with callus setose to posterior margin; bare anteriorly between spiracle and foramen. Gaster (Fig. 38) about 1.7× as long as mesosoma; with sparse, inconspicuous white setae dorsally and somewhat more conspicuous, slightly lanceolate white setae laterally; penultimate tergum with posterior margin extending to level of cerci; syntergum only very slightly longer than transcercal width, evenly convex, and about as long as penultimate tergum. MALE (Fig. 48). ALLOTYPE: length 1.4 mm. Similar to holotype except as follows. Color. Mostly brownish (Fig. 48) with much less distinct metallic lusters, only lower face with distinct greenish luster under some angles of light and propodeum somewhat bluish-violaceous; legs with about medial third of posterior surface of mesofemur brownish, all but about apical quarter of metafemur brown, and dorsal surface of metatibia more extensively brownish. Structure/setation. Head in dorsal view about 1.75× as wide as long, with IOD about 0.48× head width; IOD: MPOD: OOL: POL: LOL = 33: 8: 4: 15: 8; in frontal view about 1.25× as wide as high, with ventral margin of torulus about at level of lower orbits; malar space about 0.56× eye height. Antenna with flagellum conspicuously setose and elongate-filiform, the curved setae somewhat longer than width of respective flagellomere; length of flagellum + pedicel about 2.1× width of head; scape: pedicel: fu1–fu11 = 21(8): 10(7): 2(4), 14(5), 16(5), 16(6), 15(6), 15(6), 13(6), 13(6): 13(6): 10(5): 12(5) (including very small apical subsegment). Fore wing with cc: mv: stv: pmv = 50: 55: 10: 12; oblique bare band behind marginal vein distinct for both wings. Scutellum elongate-reticulate rather than distinctly strigose. Metacoxa with outer surface bare mediolongitudinally except for single row of setae along basal margin. Variation. Females range in length from about 1.5–3 mm and males from about 1.3–2 mm. The metallic lusters of the body vary in intensity, smaller individuals usually being more brownish with less distinct metallic lusters and larger specimens often having the mesoscutum broadly brown with coppery luster medially and the lateral lobes with variably extensive, though quite dark and comparatively inconspicuous green, bluish and/or purple lusters under some angles of light. Females sometimes also have the extreme base of the scape white, the fore wing setae more whitish, though not obviously lighter behind the submarginal than the marginal vein, and the hind legs less extensively brown or rarely completely yellow beyond the metacoxa. Setal pattern of the fore wing disc varies in both sexes. Some specimens have an essentially uniformly setose disc, including a uniformly setose mediocubital fold that extends somewhat basal of the level of the basal fold, whereas others have quite a distinct, posteriorly open bare band along the parastigma and basal fold and/or quite a distinct linea calva (cf. Fig. 58). When present, the two bare bands are usually separated by setae, but in some specimens the linea calva is continuous with the basal bare band. Some females have the mesoscutum more uniformly, though extremely shallowly meshlike reticulate (Fig. 76) to almost coriaceous, the cells defined by only very slightly raised ridges similar to most males. Some females also have the scutellum more distinctly elongate-reticulate than strigose and smaller females tend to have slightly shorter funiculars such that the apical ones are quadrate rather than slightly elongate. I exclude from the type series of C. albipalpus two males from Dominica that have the mesoscutum mostly smooth and shiny mediolongitudinally anterior to the base of the scutellum (only extremely obscure meshlike coriaceous sculpture under some angles of light), the fore wings more extensively setose (disc without evident bare regions and about apical half of cubital area closed by setae posteriorly) than for other males, and the tegula yellow similar to males of C. setosa. These males likely belong to a different species than C. albipalpus, but females from Dominica are required to adequately assess variation and species limits.

Distribution. New World, extending between about 35°N in North America and 10°N in South America (Map 1). Calosota albipalpus is one of four species comprising a species complex that is united both by head sculpture and distribution. All specimens of Calosota seen from the New World south of the USA have a finely coriaceous frontovertex and a mostly smooth and shiny scrobal depression, suggesting that they comprise a species group that possibly evolved in the Neotropical region, of which some of the species (C. albipalpus, C. speculifrons and C. setosa) subsequently expanded their ranges into southern USA.