Key to genera and species of Cerasommatidiidae

1. Trochanters flaưened, projected to cover tibio-tarsal joint in repose (Figs 4E, 4, 5H, 7K, 9F, 10F, 11F, 18E); vestiture of dorsal body surface uniform (tiny decumbent hairs (offen missing)) (Figs 4B, C, 5C, G, 18C, F) or moderately long suberect setae (Figs 9E, 10C, 11B, D) ........................................................................................................................................................................2

- Trochanters normal, not flaưened or produced to cover tibio-tarsal joint in repose (Figs 13D, 15D, G, 16D); vestiture of dorsal surface of body composed of minuscule decumbent hairs and sparse long erect setae (Figs 15F, 16B) [Puerto Rico, Venezuela]......................................................................................................................................................................................... Yamuy ...4

2. Pronotum with lateral and anterior borders simply margined (Figs 4B, 5C, 18C); dorsal surface with tiny decumbent hairs (offen missing) (Figs 4B, C, 5C, G, 18C, F) .............................................................................................................................................3

- Pronotum with lateral margins bordered with an internal subparallel carinae (Figs 9C, 10C, 11B); anterior margin of pronotum with crenulate bordering line (Figs 9C, 10C, 11B); dorsal surface with moderately long suberect pubescence (offen missing) (Figs 6A–F, 9E, 10C) ................................................................................................................................... Karumbe ....5

3. Abdominal ventrite 1 with complete semicircular postcoxal lines (Figs 3D, 4G, 5H); prosternal process with long lateral carinae reaching anterior third of prosternum, without median carina (Fig. 5D); Brazil ............................. Cerasommatidia …7

- Abdominal ventrite 1 without postcoxal lines, only with anterior bordering margin thickened posterior to coxae and widening laterally (Fig. 18G); prosternum with raised, single, median carina, (Fig. 18D); Madagascar ............. Mahavelo madagasus

4. Pronotum with lateral margins bordered with an internal carina (Figs 12C, D, 16B); anterior margins of metaventrite and abdominal ventrite 1 with small longitudinal carina below each coxa (Fig 16D, F); Puerto Rico ................. Yamuy marginatus

- Pronotum with lateral margins only narrowly bordered with simple bordering line, with internal carina short, weakly marked, present only basally (Fig. 15C); anterior margins of metaventrite and abdominal ventrite 1 without longitudinal carinae beyond coxae (Figs 13D, 15G, H); Puerto Rico, Venezuela ........................................................................ Yamuy constratus

5. Body more than 1.40 mm long; metaventrite with setiferous punctures inserted in wide foveate impressions (Fig. 9F); terminal labial palpomere elongate and acuminate, 2.2 times as long as wide (Fig. 9B); Brazil ............................. Karumbe brethesi

- Body less than 1.00 mm long; metaventrite with simple setiferous punctures (Figs 10E, 11F); terminal labial palpomere short and apically rounded, 1.2–1.4 times as long as wide (Figs 7D, 10A); Venezuela, Grenada ..6

6. Prosternal process narrower, about 0.67 of width of procoxal diameter (Fig. 11C); pronotum with postero-lateral indentation short and rectangular (Fig. 11B); Venezuela ..................................................................................................... Karumbe pakaluki

- Prosternal process wider, about 0.90 of width of procoxal diameter (Fig. 10B); pronotum with postero-lateral indentation large and oblique (Fig. 10C); Grenada ............................................................................................................................ Karumbe geiseri

7. Pronotum 2.0 times as wide as long, with bordering line at anterior margin complete; body size about 1.7 mm ............................................................................................................................................................................... Cerasommatidia rotundata

- Pronotum at least 2.2 times as wide as long, with bordering line at anterior margin vanishing medially; body size 1.1–1.4 mm ............................................................................................................................................................................................................................8

8. Body 1.15 mm long; posterior margin of pronotum narrowly bordered at least medially (Fig. 5C); aedeagus as in Fig. 3E ............................................................................................................................................................................. Cerasommatidia plaumanni

- Body 1.4 mm long; posterior margin of pronotum not bordered (Fig. 4B); aedeagus as in Fig. 3F ...... Cerasommatidia arrowi