Key to Lachesilla species of the pedicularia group in which males have one clunial apophysis

1. Females............................................................................................ 2

-. Males............................................................................................. 6

2. Subgenital plate posteriorly rounded; ninth sternum anteriorly rounded, spermapore towards anterior margin................................................................ Lachesilla cesarcardonai García Aldrete, González & Saldaña

-. Subgenital plate posteriorly bilobed; ninth sternum with a transverse pigmented area............................... 3

3. Subgenital plate and paraprocts broadly triangular; epiproct concave anteriorly; ninth sternum with broad pigmented area; spermapore small, towards anterior margin............................. Lachesilla asymmetriproctus García Aldrete

-. Subgenital plate broad, with or without a pigmented area underlying the plate...................................... 4

4. Subgenital plate extended posteriorly; gonapophyses short and slender; ninth sternum narrow; epiproct concave anteriorly; without a pigmented area underlying the subgenital plate...................... Lachesilla convexicornis García Aldrete

-. Subgenital plate with a broad, irregular pigmented area on each side of longitudinal midline (Fig. 17); epiproct with or without a pigmented basal area................................................................................. 5

5. Gonapophyses large; ninth sternum almost rectangular; epiproct almost straight anteriorly, uniformly pigmented; with an irregular pigmented area on each side of longitudinal midline, underlying the subgenital plate................................................................................................. Lachesilla macropudenda García Aldrete

-. Gonapophyses large and slender; ninth sternum membranous, with two rounded, well sclerotized areas and with a narrow transverse band distally (Fig. 18); epiproct rounded posteriorly and concave anteriorly (Fig. 19) Lachesilla huitoto n. sp.

6. Epiproct without apophyses; clunial apophysis short and stout; phallosome apodeme stout, branching distally, “Y” shaped..................................................................... Lachesilla macropudenda Garcia Aldrete

-. Epiproct with two apophyses; phallosome apodeme “Y” or “T” shaped; claspers tips free or fused...................... 7

7. Phallosome apodeme “Y” shaped; claspers not fused distally; epiproctal apophyses almost straight and slender; clunial apophysis long, slender, apically pointed and considerably exceeding the distal margin of the epiproct.......................................................................... Lachesilla cesarcardonai García Aldrete, González & Saldaña

-. Phallosome apodeme “T” shaped; claspers tips fused; clunial apophysis not exceeding the distal margin of the epiproct or shorter.............................................................................................. 8

8. Epiproctal apophyses strongly asymmetric; clunial apophysis stout, slightly curved and obtusely concave at apex, not exceeding the distal margin of the epiproct................................... Lachesilla asymmetriproctus García Aldrete

-. Epiproctal apophyses symmetric; clunial apophysis variable................................................... 9

9. Epiproctal apophyses short, not extended or slightly extended beyond the base of the clunial apophysis................ 10

-. Epiproctal apophyses large considerably extended beyond the base of the clunial apophysis…....................... 12

10. Epiproctal apophyses forceps-like (Fig. 4), slightly extended beyond the base of the clunial apophysis; clunial apophysis long, slender and widened at the apex; claspers fused distally, forming a projection slightly bifurcated at apex (Fig. 6)...................................................................................... Lachesilla putumayensis n. sp.

-. Epiproctal apophyses not forceps-like, short and clunial apophysis short......................................... 11

11. Epiproct bilobed, apophyses, stout, slightly curved outward; clunial apophysis broad, stout, concave distally; claspers fused distally, forming a projection slightly bifurcated at apex....................... Lachesilla convexicornis García Aldrete

-. Epiproct almost rectangular, apophyses broadly joined at base, deeply concave distally forming two acuminate arms bent outwards; clunial apophysis slender, straight at apex................................. Lachesilla williamsi García Aldrete

12. Clunial apophysis slender, wider basally, with posterior margin truncate; claspers fused distally, forming a blunt projection; epiproct bilobed, with long, acuminate apophyses.............................. Lachesilla carpinteroi García Aldrete

-. Clunial apophysis stout, broad; epiproct bilobed, with long, slender apophyses; claspers fused distally, forming a projection bifurcated or acuminate at apex........................................................................ 13

13. Claspers forming an acuminate projection; clunial apophysis almost as long as wide, with posterior margin straight; epiproctal apophyses long, curved, distally acuminate...................... Lachesilla ilama García Aldrete, González & Saldaña

-. Claspers forming a projection bifurcated at apex (Fig. 12).; clunial apophysis longer than wide, with posterior margin straight (Fig. 10) or slightly concave (Fig. 22); epiproctal apophyses long, almost straight, curved at apex, with a short, broad spine on the inner margin of basal half (Figs 10, 22).............................................. Lachesilla huitoto n. sp.