Key to Mexican genera of Hesperophanini (adapted from Chemsak and Linsley 1984)

1. Femora strongly clavate................................................................................ 2

- Femora not or at most feebly clavate...................................................................... 3

2(1). Pronotum with sides rounded, disk flat, with at most a small, post-median smooth callus; palpi very unequal, apex almost securiform; antennae 11-segmented......................................... Austranoplium Chemsak and Linsley, 1963

- Pronotum with sides angulate or feebly tuberculate, disc irregular, with three elevated calli; maxillary palpi only slightly longer than labial; antennae 12-segmented................................................. Malobidion Schaeffer, 1908

3(1). Pronotum tuberculate at sides............................................................................ 4

- Pronotum rounded or sinuate at sides, not tuberculate nor spinose................................................ 7

4(3). Basal antennomeres spinose at apex...................................................................... 5

- Basal antennomeres not spinose at apex................................................................... 6

5(4). Elytra without small, rounded glabrous spots............................................ Eucrossus LeConte, 1873

- Elytra with small, rounded glabrous spots............................................. Megosmidus Hovore, 1988

6(4). Elytra with sparsely scattered shining punctures............................................ Perilasius Bates, 1880

– Elytra without scattered shining punctures................................... Oraphanes Chemsak and Linsley, 1984

7(3). Vestiture of elytra dense except for small glabrous spots...................................................... 8

- Vestiture of elytra sparse to dense, or condensed............................................................ 10

8(7). Pronotum without prominent, elevated, glabrous discal callosities; elytra not granulate............ Osmidus LeConte, 1873

- Pronotum with prominent, elevated, glabrous discal callosities; elytra granulate basally or denuded spots raised.......... 9

9(8). Third antennal segment distinctly sulcate dorsally; antennae of male elongate, exceeding elytral apex by four segments; sutural angle of elytra dentate; elytra not irregularly granulate at base at most with glabrous raised spots..... Perilasius Bates, 1880

- Third antennal segment not sulcate dorsally; antennae of male extending only about two segments beyond elytral apices; apices of elytra unarmed; elytra granulate basally............................................ Brothylus LeConte, 1859

10(7). Antennae short, not or barely extending beyond middle of elytra; pronotum coarsely alveolate-punctate or not, without discal calli............................................................................. Anatinomma Bates, 1892

- Antennae elongate, extending beyond middle of elytra; pronotum finely to coarsely punctate, or asperate, not densely alveolate-punctate, discal callosities present.................................................................... 11

11(10). Scape strongly, irregularly compressed at basal half......................... Austrophanes Chemsak and Linsley, 1963

- Scape not compressed................................................................................ 12

12(11). Pubescence condensed into patches on pronotum and elytra; pronotum granulate-punctate........ Cacophrissus Bates, 1885

- Pubescence not condensed into patches on pronotum and elytra; pronotum not granulate-punctate.................... 13

13(12). Palpi with apical segments expanded; disk of pronotum with round, elevated calli............. Xeranoplium Linsley, 1957

- Palpi with apical segments not expanded; disk of pronotum without round, elevated calli........................... 14

14(13). Antennae in males notably surpassing elytral apex; tibiae carinate laterally; apices of elytra with spine at sutural angle.......................................................................... Heteraneflus Chemsak and Linsley, 1963

- Antennae in males, at most, slightly surpassing elytral apex; tibiae not carinate laterally; apices of elytra without apical spines.................................................................................................. 15

15(14). Mandibles in male long, falciform; head, including eyes, about as wide as humeral width.......... Makromastax gen. nov.

- Mandibles in male short, not falciform; head, including eyes, narrower than humeral width, but if with similar width, body distinctly slender..................................................................... Haplidus LeConte, 1873