Key to the species of Elaphopsocus [males]

1. Hypandrium simple, without posterior projections............................................................ 2

-. Hypandrium bearing a long posterior projection on each side (Figs 48, 49)............................ E. roesleri n. sp.

2. Posterior angle of pterostigmal apex not rounded, "v" shaped (Fig. 52)........................................... 3

-. Posterior angle of pterostigmal apex rounded (Fig. 53)....................................................... 5

3. Aedeagal arch straight posteriorly (Fig. 36). Epiproct with a field of papillae posteriorly. Clunium with a field of papillae over the area of the epiproct (Fig. 33)............................................................ E. bahianus n. sp.

-. Aedeagal arms not forming an arch. Clunium and epiproct not papillose.......................................... 4

4. Aedeagal arms bent in the middle at an angle of 90º; phallobase more than half the length of the phallosome (Fig. 30)............................................................................................... E. rayoi n. sp.

-. Aedeagal arms bent distally at an angle of about 50º; phallobase less than half the length of the phallosome (Fig. 18)............................................................................................. E. gorrones n. sp.

5. Phallosome with aedeagal arms deeply cleft. External parameres sigmoid (Fig. 41).................. E. amazonicus n. sp.

-. Phallosome with external parameres slender or dilated distally.................................................. 6

6. Phallosome with external parameres antler-like (Fig. 51)................................. E. glaphyrostigma Roesler

-. Phallosome with external parameres dilated posteriorly, bearing on inner side a hook like projection (Fig. 5)... E. nasa n. sp.