98 PROCEEDINGS OF THE NATIONAL AIUSEUM vol. in 



the many yellowish spots are so t3rpical of 0. arisonensis, we have 

 concluded that arizonensis must be a synonym of hopjneri. Onthopha- 

 gus hopjneri males vary from very small (3.1 mim.) specimens lacking 

 any trace of the pronotal protuberance but with a very distinct frontal 

 carina, a mere suspicion of an anterior clypeal carina, and few or no 

 round spots in elytral black band, to much larger specimens (6 mm.) 

 with a well-developed conical pronotal protuberance, no head carinae, 

 and numerous round spots on the elytra. 



Mexican and more southern specimens seem to be smaller, the 

 yellow part of the elytra is wider anteriorly, the humeral umbone is 

 yellow, there are fewer yellow spots on the median band, the pygidium 

 is black, the pronotal punctures are not quite so deep and clear cut, 

 and each seta is near the anterior of the punctiu-e and at its base has a 

 more evident tubercle. Arizona specimens are usually larger, the 

 yellow base of elytra narrower, the humeral umbone and fifth sutural 

 near base black, the pygidium bicolored. 



0. hopjneri is separated from alUed and other United States species 

 by its size and by the color of the elytra, particularly the usually nu- 

 merous, small, round yellowish spots on the black backgi'ound across the 

 middle of the elytra. Males usually have a small conical pronotal pro- 

 tuberance, and the elongated foretibiae terminate mth a pencil of 

 long hairs and a tooth above the apical spur. 



This species has been taken only in south central Arizona. Series 

 of specimens have been examined from Tucson, Patagonia, and the 

 Baboquivari Mountains (particularly Browns Canyon). It seems to 

 be a general dung feeder; the majority of specimens were collected in 

 July and August. Nothing has been recorded on its hfe history. 



Onthophagus arnetti, new species 



Plates 7, Figures 68 and 69; 8, Figure 76 



HoLOTYPE. — Male major, length 8.6 mm., width 4.8 mm. Head, 

 except clypeus, and pronotum dark green, clypeus and elytra black; 

 finely alutaceous, feebly shining. Clypeus abruptly reflexed an- 

 teriorly only, the reflexed portion widely arcuate; disc of clypeus 

 slightly concave, with mixed coarse and fine punctures, shghtly rugose 

 laterally; clypeal carina a fine raised line extending from margin to 

 margin; frons shghtly convex, moderately punctate, some punctures 

 with erect setae; surface between punctures very finely alutaceous; 

 gena with margin extended laterally further than lateral clypeal 

 margin, obtusely angulate with clypeus; surface of gena coarsely 

 setigerously punctate ; eye noticeably convex and nearly twice as wide 

 as eye of either velutinus or hrown.i\ frontal carina obsolete medially; 

 laterally the sharp carina highest at abrupt terminations behind the 

 eyes; surface behind carina with a few coarse setigerous punctures. 



