100 U.S. NATIONAL MUSEUM BULLETIN 25 6 



There is one generation annually. Emergence commences in May 

 and reaches its height in July. Field observations during several years 

 have indicated that adults are most abundant in July and August. 

 Beetles collected in July were mostly alive in Uvalde cages at the end of 

 October and were still actively feeding in December; many lived 

 through the winter, and the last survivor died in late April, a longevity 

 record of 9% months. The eggs are deposited from June to August. 

 Adults in cages laid freely during July and the first half of August, 

 deposited few eggs in the second half of August, and laid none sub- 

 sequently, although they were feeding regularly until December. An 

 incubation period of 21 days was recorded at Uvalde in July. From 

 eggs that hatched in July and August, the larvae developed rather 

 slowly and were not more than one-third to one-half grown in January. 



Moneilema pollens Casey 



This form is very closely related to M. gigas. Adults were collected 

 at Hermosillo, State of Sonora, Mexico, in August 1922, and were 

 abundant on the Cylindropuntia 0. Julgida at Empalme, Sonora, 

 in August 1926. This species appears to be intermingled with M. 

 gigas in the Quijotoa Mountains of southwestern Arizona. 



Moneilema pimalis Casey 



This is another close relative of M. gigas. Adults were taken at Culiacan, 

 State of Sinaloa, west coast of Mexico, in August 1926. 



Moneilema spoliata Horn 



This Californian black species of medium size does not seem to be 

 prevalent. Adults have been collected in small numbers in June 

 on prickly pears and on the Cylindropuntia 0. bernardina in the Cuya- 

 maca Mountains and in July on the Cylindropuntia 0. echinocarpa 

 in San Gorgonia Pass. A doubtful record would suggest its occurrence 

 in western Arizona; beetles captured near the Williams River were 

 either this species or one of the Utah forms M. obtusa or M. appressa. 



Moneilema obtusa LeConte 



This is another moderate-size black species. Adults have been collected 

 in July at Cedar City and Zion National Park, Utah, and at Lees 

 Ferry in northern Arizona. In the Zion National Park a very ex- 

 tensive area of Opuntia imbricata showed considerable damage as 

 a result of the activities of the larvae. 



