Key to the Mexican genera of Tanymecini

1 Metatibial apex simple (figures 1 and 2)................................................................... 2

1’ Metatibial apex with false or true corbels (figures 3–6)........................................................ 6

2 Anterior margin of abdominal ventrites 3–5 flat, not sulcate (figure 7); front legs generally greatly larger than middle and hind legs................................................................................................ 3

2’ Anterior margin of abdominal ventrites 3–5 sulcate across almost entire width of abdomen or medially only (except Isodacrys minutum) (figure 8); front legs from not at all enlarged to slightly larger than middle and hind legs..................... 4

3 Mandibles on lateral and ventral surface with scales; front coxae contiguous or narrowly separated.......... Hadromeropsis

3’ Mandibles without scales; front coxae distinctly separated................................ Pandeleteius (Pandeleteius)

4 Tarsal claws connate............................................................................ Isodrusus

4’ Tarsal claws free...................................................................................... 5

5 Humeri well developed; with postocular vibrissae well developed or reduced to 1–3 hairs.................. Pandeleteinus

5’ Humeri rounded to partially developed (figure 15); with or without postocular vibrissae...................... Isodacrys

6 Metatibial apex with false corbels; humeri well-developed, oblique or quadrate; tarsi 1–3 on ventral surface with pads of setiform setae........................................................................................... 7

6’ Metatibial apex with true corbels; humeri rounded; tarsi 1–3 on ventral surface with stout, spiniform setae instead of pads of setiform setae; apex of hind tibae bearing conical to lameliform bristles, shorter to subequal in length to the surrounding setae.......................................................................................... Minyomerus

7 Dorsal surface of rostrum apicad of antennal insertion elevated in a platform consisting of an apical glabrous portion followed by a squamose portion, with posterior margin ending in a transverse inter-antennal groove; front legs distinctly larger than middle and hind legs; front coxae separated; hind tibia without straight comb of setae on outer edge.................... 8

7’ Dorsal surface of rostrum apicad of antennal insertion not elevated in a platform; front legs not larger than middle and hind legs; front coxae contiguous; hind tibia with straight comb of setae on outer edge, comb at least as long as width of tibia at apex............................................................................................. Tanymecus

8 Rostrum with apical glabrous portion of platform not separated from the squamose portion by a carina (figure 9); vibrissae present....................................................................................... Airosimus

8’ Rostrum with apical glabrous portion of platform separated from the squamose portion by a carina (figure 10); ocular vibrissae absent........................................................................ Pandeleteius (Exmenetypus)