Menoscelis Mulsant, 1850

Menoscelis Mulsant, 1850: 506, 508; Crotch, 1874: 209; Gemminger & Harold, 1876: 3783; Chapin, 1966: 279; El-Ali, 1972: 23; Gordon, 1987: 26; Milléo et al., 2004: 395; Gordon & Canepari, 2008: 271 –274.

Menoscelis (Thalassa): Chapuis, 1876: 228, 233–234.

Thalassa (Menoscelis): Korschefsky, 1931: 208; Blackwelder, 1945: 449; Duverger, 1989: 146; Fürsch, 1990b: 63.

Type species. Menoscelis saginata Mulsant, 1850, by subsequent designation of Crotch (1874).

Diagnosis. Menoscelis is a Neotropical genus that is structurally similar to Diazonema Weise, 1926, but differs from all other genera of the tribe in the highly modified protibia, angulate near its base (Figs 5 D–E) and the transverse female genital plate with spoon–like setae near the apex. Diazonema presents a combination of short and compressed protibia, and a transverse female genital plate lacking spoon–like setae near the apex.

In addition to the generic characters described by Gordon & Canepari (2008), species of this genus have other useful characters that aid in their recognition: body usually large (4.5–7.5 mm) and rounded, moderately to strongly convex. Dorsal surface glabrous or pubescent, maculate or not. Prosternum process about half the coxal diamenter, surface with complete or incomplete carinae joined anteriorly, forming a triangle (Figs 5 C, 6E). Prosternal carinae often joined, sometimes connected to the anterior margin of the prosternum by a single carina (Figs 8 A–G, 9A–E). Epipleura large, external margin explanate (Figs 5 H, 6H). Protibia flattened, medially emarginate or with parallel sides, tibial groove deep, long, not flanged posteriorly, angulate near base (Figs 5 D–E, 6F–G); meso- and metatibia narrow, medially emarginate or with parallel sides, not flanged, with shallow tibial groove (Figs 5 F, 6I). Abdominal postcoxal line incomplete, recurved or slightly recurved (Figs 5 G, 6J). Parameres symmetrical; basal lobe asymmetrical. Sipho slender with well-developed, T-shaped siphonal capsule (Figs 1 E–G, 4D–F). Coxites transverse with spoon-like setae near apex, styles well developed, with or without apical setae; infundibulum lacking; sperm duct simple, uniform in diameter (Figs1 H, 2E, 3F). Spermatheca with rounded cornu and narrow at base; distal capsule adjacent to cornu or sperm duct (Figs 2 F, 3G).

Remarks. Two species, M. angeloi sp. nov. and M. cordata sp. nov., lack the protibial emargination but are considered members of Menoscelis due to the described characters and male and female genital patterns.