CACTUS-FEEDING INSECTS AND MITES 97 



149 days. The highest number of eggs from an individual female has 

 been 27, but probably the maximum fecundity is greater than this 

 figure would indicate. In small cages the males and females fought 

 violently, soon becoming disabled through the loss of legs and antennae; 

 usually the male was the victor. 



Parasites. — A braconid, Vipio moneilemae Gahan, destroyed many 

 pupae in the field at Aguascalientes in May-June 1927; from 10 to 

 15 parasite pupae were found in each host cocoon, and the adult 

 braconids emerged in September. This insect has been reared from 

 cocoons of M. obtusa collected at Cedar City, Utah, in July 1926. 



Moneilema rugostpennts Fisher 



This species was described in 1928 from specimens collected during 

 the investigations at San Luis Potosi, Mexico, in May and June 1927. 

 It is a ratlier large, very shiny black beetle, related to M. armata; 

 in both forms the newly-emerged adults are covered with a light 

 powdery bloom which is soon lost by abrasion. The beetles appear to 

 be the most aggressive of this genus; they have been known to escape 

 from cages by chewing through copper-gauze screen. 



The species has been obtained from the general vicinity of San Luis 

 Potosi, and from Torreon on the border of the State of Coahuila and 

 Durango, but it must occur in the State of Zacatecas. It was very 

 abundant in some seasons at San Luis Potosi, and was fairly common 

 at Torreon. In the latter area the host plant was the Platyopuntia 

 0. rufida; the larvae attacked the short main stem, causing the plant 

 to topple and die; considerable destruction among fields of this plant 

 was reported in October 1926. At San Luis Potosi various prickly 

 pears were infested quite freely, but a distinct preference was observed 

 for the Cylindropuntia 0. imbricaia; in 1928 some fields of imbricata 

 had been almost completely wiped out by the attack. 



There is an annual generation. Adults have appeared in April, 

 but the main emergence is in May and June. In 1928 beetles com- 

 menced to emerge in late May and were abundant within a few days. 

 The eggs are laid in May and June. During the winter the larvae 

 become full grown and form cocoons in February to April. Adults 

 can survive for six months. In the field they have been seen in fair 

 numbers in October and some were still actively feeding in November; 

 from material collected in May, some survivors remained in the cages 

 in December. 



Moneilema armata LeConte 



This species is of moderate size, rather shiny black but not as shiny 

 as its ally M. rugosipennis, and with a powdery bloom on freshly-emerged 



263-417—68 8 



