Key to females of Centris (Heterocentris) with horns on the clypeus 1 Clypeus with two horns, each located at side of the clypeus............................ Centris bicornuta (Figs. 9–10) 1’ Clypeus with a single horn located centrally or near the epistomal suture.......................................... 2 2 Mandible dark brown, longer than the length of the eye (frontal view) and with two teeth relatively similar in size located in the distal half; disc of mesoscutum and external side of hind tibia with brown hairs; metasoma dark brown.................................................................................................. Centris cornuta (Figs. 7–8) 2’ Mandible predominantly yellow (except apex), shorter than the length of the eye (frontal view) and with the apical teeth differing in size (except C. adunca (Figs. 5–6) with only one apical tooth); disc of mesoscutum and external side of hind tibia with yellowish hairs; metasoma with orange integument.......................................................... 3 3 Horn compressed dorsoventrally and with acute apex, surpassing the lower margin of the clypeus (Figs. 1 and 2); mandible gently curved apically and with two teeth in the apical half; distal margin of labrum convex.... Centris ceratops new species 3’ Horn not compressed dorsoventrally and with bifid apex, not exceeding the lower margin of the clypeus; mandible apically angled and with only one tooth in the apical half; distal margin of labrum biconvex............ Centris adunca (Figs. 5–6)

Published as part of Vélez, Danny & Vivallo, Felipe, 2012, A new South American species of Centris (Heterocentris) Cockerell, 1899 with a key to the species with horn-like projections on the clypeus (Hymenoptera: Apidae: Centridini), pp. 49-55 in Zootaxa 3357 on page 54, DOI: 10.5281/zenodo.211216