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PROCEEDINGS OF THE NATIONAL MUSEUM 



Type. — Canadian National Collection 7530. 



Type locality. — Pena Blanca Canyon (3800 ft.), Santa Cruz Co., 

 Ariz. 



Specimens examined, — Holotype, allotype, and one paratype. 

 Distribution. — (See fig. 10.) 



Arizona: Pena Blanca Canyon, Santa Cruz Co. The holotype was collected at 

 black light, July 24, 1960, by Killian Roever, and the allotype by Ross H. Arnett, 

 Jr., July 23, 1959. Paratype, cf, Patagonia, (E. R. Leach coll., cas). 



Remarks. — This species is easily separated from other North 

 American Onthophagus by the following combination of characters: 

 Dark green head and pronotum with dull black elytra; large convex 

 eyes; small circular pronotal tubercles separated by two or more 

 diameters; short reddish setae at the base of the tubercles on both 

 pronotum and elytra; very broadly rounded anterior angles of the pro- 

 notum; the moderately large size, 6.6 to 8.6 mm, in length. 



0. velutinus, 0. brovmi, and 0. arnetti are all about the same size, 

 alutaceous and feebly shining, with rather evenly distributed, well- 

 separated tubercles; however, arnetti is green and black, velutinus dark 

 brown, and brovmi black; the anterior angles are much more broadly 

 rounded in arnetti. Viewed laterally, the posterior angles are sharper 

 in arnetti, measuring 130° in arnetti, 140° in brovmi, and 145° in 

 velutinus, and the margin between the anterior and posterior pronotal 

 angles is nearly straight in arnetti and noticeably sinuate in the other 

 two; the pronotal protuberance of the female arnetti is intermediate 

 in development compared to the others. In arnetti the eyes are much 



Figure 10. Distribution of species of Onthophagus: 

 # nuchicornis (Linnaeus) O medorensis Brown -^ arnetti, new species 



