BEETLE GENUS ONTHOPHx\GUS — HOWDEN, CARTWRIGHT 25 



very slightly convex, basally with two long, widely separated verti- 

 cal horns sliglitly ciu'ved forward and weakly bowed laterally, the 

 horns somewhat flattened transversely with rounded edges, not con- 

 nected by a basal carina; punctures of head very fine medially, 

 separated bj^' two or more diameters, somewhat larger laterally, 

 particularly on the genae. 



Pronotum finely, completely margined; anterior angles sharply 

 rounded but not acute, posterior angles broadly rounded; median 

 protuberance vertical in front, quite high, the broad rounded sum- 

 mit with a very weak longitudinal, median depression, laterally rounded 

 into a strong vertical cavity each side to receive the cephalic horns. 

 Punctures fine in anterior angles and median groove of protuber- 

 ance, about as on genae, gradually finer away from these areas to 

 the disc and base; the disc sometimes almost impunctate, lateral 

 foveae strong. Elytra shining, rarely very finely alutaceous; striae 

 fuie, the punctures slightl}^ crenating the intervals; intervals weakl}^ 

 convex, all finely, quite closely, confusedly punctate, the scattered 

 punctures separated by 1 to 2 diameters. Pygidium weakly, evenly 

 convex, very finely alutaceous, and not as shining as upper surfaces; 

 punctures close, very slightly larger and deeper than on elj^tra, occa- 

 sionally with a few in rov/s between transverse wrinkles. Legs dark, 

 almost black, the anterior tibia with a blunt, slightly upturned tooth 

 at the tip above the spur; club of antennae fuscous. 



Male minors. — Variation is toward the female in reduction in 

 the length of the cephalic horns, the pronotal prominence, and the 

 accompan^'ing lateral cavities. The only noticeable difference be- 

 tween the least developed male seen and a female was the complete 

 absence of the clypeal carina, the presence of the anterior tibial tooth, 

 and the narrowed apex of the terminal abdominal segment. 



Females. — Length 7.5 to 10 mm., width 4.75 to 6 mm. Differing 

 from males as follows: Punctation usually more noticeable, closer, 

 and deeper on the upper surface ; no tooth or tubercle above the spur 

 of the anterior tibia; the tenrdnal abdominal segment not narrowed 

 apically; clypeus longer, rounded, and not noticeably emarginate- 

 truncate or reflexed; clypeal carina well developed and noticeably 

 higher at middle ; frontal carina also well developed but usually slightly 

 lower and posteriorly angulate at middle; anterior prominence of 

 pronotum weak, similar to that of male, but widely depressed medi- 

 ally and laterally reduced to rounded tubercles. 



Type. — Museum of Comparative Zoology, Harvard College, 

 Cambridge, Mass, 



Type locality. — "Mexico." Barber (1928) stated, "It is probable 

 that all of his (Say's) Mexican forms were collected along the old road 

 between Veracruz, Jalapa, Mexico City, and Tacuba." 



