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PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



Figure 2. Distribution of species of Onthophagus: 

 % pefifisylvanicus Harold O cochisus Brown 



Remarks. — In the United States this uncommon species appears 

 to be restricted to the higher elevations (5000 to 8000 ft.) of the Chiri- 

 cahua Mountains of southeastern Arizona. It seems to be a fairly 

 general feeder as an adult, being taken on carrion and under fresh 

 horse droppings. Howden took 64 specimens on July 3 under leaf 

 litter at Onion Saddle in the Chiricahua Mountains. The specimens 

 were kept alive and attempts were made to rear the specimens in 

 flower pots. Both horse and cow dung were supplied, but owing to 

 higher laboratory temperatures or other unknown factors, no larval 

 cells were formed. 



0. cochisus Brown can be separated from other American species 

 north of Mexico by its large size, its duU black alutaceous dorsal 

 surface, and the combination of a densely coarsely punctate pronotum 

 coupled with the conspicuously tuberculate elytral intervals. 



Type material of closely allied species from south of our borders 

 was examined and the following differences noted : 



0. hippopotamus Harold is slightly larger, is shining, and has punc- 

 tate rather than tuberculate elytral intervals. 



0. totonicapanus Bates is much smoother, with shallow pronotal punc- 

 tures and practically no elytral tubercles, those showing being scarcely 

 visible and very widely scattered. 



0. chevrolati Harold also is smoother in appearance, with pronotal 

 punctures finer, not as close nor as deep, and elytral tubercles much 

 finer and less conspicuous. 



