Key to Horismenus species from Phaseolus spp. in Mexico

1 Scutellum flat, posteromedian part of scutellum smooth and shiny (Figs 12–13).......... ................................................................................. depressus Gahan (female, male)

– Scutellum distinctlyconvex,posteromedianpartofscutellum reticulate(Figs4 –5,16–17) ....................................................................................................................................... 2

2 Funicular segments longer (Figs 20–21), first funicular segment 3.5X as long as wide in female, 2.5–2.8X as long as wide in male; female gaster long, ratio length of mesosoma/length of gaster = 0.8–0.9 and with apex more pointed (Fig. 6) ........................... .................................................................................... butcheri sp.nov. (female, male)

– Funicular segments short and stout (Figs 24–26), female with first funicular segment at most 1.8X as long as wide, male with first funicular segment 1.9X as long as wide (appearance of flagellum in male productus not known); female gaster short, ratio length of mesosoma/length of gaster = 1.1–1.8 and with apex more rounded (Fig. 18)33

3 Frons metallic bluish­green in female, metallic purple in male; female with first funicular segment 0.8X as long as second funicular segment (Fig. 24); female gaster longer than in alternate, ratio length of mesosoma/length of gaster = 1.1 ................................. ..................................................................... missouriensis (Ashmead) (female, male)

– Frons metallic purple in female, golden­green in male; female with first and second funicular segments equally long (Fig. 26); female gaster short, ratio length of mesosoma/length of gaster = 1.8................................. productus (Ashmead) (female, male)