104 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



Brown, Entomology Research Institute, Canada Department of Agri- 

 culture, Ottawa, who has contributed so much to the study of the 

 genus and who has been of considerable help with the present work. 



It seems odd that this species so long escaped discovery. When 

 the present study was started, the only specimen found in any collec- 

 tion was a male in the Canadian National Collection simply labelled 

 "Prescott, Ariz." and determined as undescribed by Mr. Browm. 

 Three other specimens subsequently were collected at light in Arizona 

 by Drs. Werner and Butler, University of Arizona. Then in late 

 June of 1956, when the authors were collecting with Dr. Frank Young 

 near Portal, Ariz., Dr. Young found a dead specimen under a rock 

 at the edge of a wood rat nest. This discovery led to the investiga- 

 tion of several nests in the area, 1 mile east of Portal, and the finding 

 of additional specimens. 



Most of the wood rat nests examined were built in the centers of 

 small clumps of mesquite which grew among fair-sized rocks. The 

 rats (Neotoma probably mexicana) constructed their nests of any 

 material that was handy. In this particular locality the nests con- 

 sisted largely of mesquite and Acacia twigs and bits of cactus. In 

 several nests, dried cow chips were added to the heap, as well as paper, 

 cloth, small rocks, and pieces of broken glass. The nests were 4 to 5 

 feet in diameter and several feet thick. The rats usually had several 

 entrances to the nest, with the central chamber often under a large 

 rock. It was near the end of an extremely long dry season when the 

 nests were investigated, and the ground crumbled to fine dust when 

 disturbed. 



After Dr. Young's initial discovery, the writers chose a large nest 

 and with the aid of an ax and crowbar pulled it apart. The bottom 

 of the nest yielded some fragments and dead specimens of Onthophagus 

 and Euphoria, but was largely unproductive. It was not until 

 excavation was started beneath the nest that the Onthophagus came 

 to light. More than thirty specimens were taken from the one nest 

 in 3 days of digging. Many of the specimens were dead, evidently 

 killed by the prolonged drought. The dusty rocky soil made it very 

 dijGBcult to find the beetles and almost impossible to locate the burrows, 

 for as soon as a rock was removed the soil crumbled to dust. However, 

 one live beetle was found at a depth of 5 inches in what appeared to 

 be a pupal cell beneath the underside of a rock. There was no indi- 

 cation of any dung or other food material. 



During the excavating, a few specimens of 0. brevifrons were also 

 taken, as well as a Euphoria near devulsa Plorn and several species of 

 Aphodius and Ataenius. Other insects were also numerous. 



Several live 0. hrowni were taken back to the Southwestern Research 

 Station; one male and three females were placed in a large battery 



