Mesembrinellidae, Shannon, 1926

Whitworth, Terry L. & Yusseff-Vanegas, Sohath, 2019, A revision of the genera and species of the Neotropical family Mesembrinellidae (Diptera: Oestroidea), Zootaxa 4659 (1), pp. 1-146 : 20

Key to subfamilies and genera of Mesembrinellidae

1 A large, dark brown fly (13–15 mm in length); abdomen robust, shiny black or dark brown with ST2–4 wider than long; each segment with two horizontal rows of stout black setae, one row along the posterior margin, the other in the posterior third of the segment ( Fig. 281); presutural intra-alar seta absent; setae on facial ridge ascending about half way to antennal base ( Fig. 193); male frons width 0.02/5 of head width at narrowest. Male terminalia with surstylus slender and straight, cercus long and slender with uniform curve forward ( Figs 101–102). Phallus in lateral view with epiphallus short and angled forward ( Fig. 191); in dorsal view with pair of lateral processes just behind hypophallic lobes ( Fig. 192). Female: spermathecae bulbous ( Fig. 410); T6 of terminalia of FU shape, T7 large and rectangular, recessed midway anteriorly ( Fig. 325); [known from Brazil, Costa Rica, Ecuador, Guatemala, Panama, Trinidad, Venezuela].............................................................................................. Souzalopesiellinae [genus Souzalopesiella ; one species, Souzalopesiella facialis ]

- A usually smaller fly (most species 12 mm or less in length); abdomen usually shiny, with metallic highlights; setae on sternites usually much weaker and not limited to two rows; sternites usually rounded, not quadrate. Male epandrium, cerci and surstyli as in Figs 15–100; phallus without lateral processes ( Figs 105–190). Females usually with spermathecae filiform or tuberform, not bulbous (except in M. flavicrura ); T6 of terminalia usually not of FU shape (except Laneella )..................... 2

2 Male with surstylus and cercus both curving forward ( Figs 15, 17, 19, 21, 23); phallus in lateral view with epiphallus long and slender, curving backward ( Figs 105, 107, 109, 111, 113); phallus in dorsal view with hypophallic lobes short and circular or semicircular ( Figs 106, 108, 110, 112, 114); frons narrow, 0.01–0.02 of head width at narrowest. Females with tuberform spermathecae ( Figs 370–374), shorter but still tuberform ( Fig. 371) in L. fuscosquamata ; T6 of FU shape ( Figs 284–286). Five of six species in this genus with a more or less shiny brown thorax (one species shiny blue), all medium-sized (10–13 mm); two species with basal half of tarsal claws pale white to pale yellowish ( Fig. 10). [Known from Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Mexico, Paraguay ( Marinho et al. 2017) and Venezuela]...................................................................................... Laneellinae [genus Laneella ; six known species]

- Male normally with surstylus curved backward or straight and cercus curved forward; phallus in lateral view usually with epiphallus short to moderate in length; hypophallic lobes rarely circular but usually narrow or, if wider, more elongate; frons width variable. Females usually with filiform spermathecae (except bulbous in M. flavicrura ; Fig. 397), most species with some metallic blue to black colors on abdomen in both sexes; female with T6 usually not so flattened, usually of distinct inverted U or V shape ( Figs 287–313); widespread from southern Mexico to Argentina............................................................................... Mesembrinellinae [genus Mesembrinella ; 6 species-groups and 48 species]