CACTUS-FEEDING INSECTS AND MITES 91 



female beetles produced 12,462 adult progeny, a return of 36 beedes 

 from each female parent. 



It has been stated that the larvae feed in the toughest and most 

 woody stems of the tree pears. Their activities set up a considerable 

 amount of decay, the branches and main stems being reduced to 

 shells of chewed fibre. The weightier branches, even the main trunks, 

 frequendy break off at a point where the full-grown larvae are working, 

 and large plants of 0. tomentosa and 0. streptacantha may be completely 

 destroyed by this insect. 



PARMENOSOMA Schaeflfer 



This genus, which is closely related to Moneilema Say, contains one 

 species from the United States diat attacks cactus. 



Parmenosoma griseum Schaefifer 



This small longicorn, which was described in 1908 from a single speci- 

 men collected at Edinburg, Hidalgo county, southern Texas, was 

 not encountered during the investigations. However, in 1935 G. W. 

 Barnette, who had formerly been on the Board's stafT, reared several 

 adults from larvae found in the stems of the prickly pear Opuntia 

 lindheimeri at Cotulla, southern Texas. Apparendy this insect is very 

 rare. 



MONEILEMA Say 



This genus, containing many more or less closely related species, 

 is a true cactus complex and primarily an Opuntia-enemy group. The 

 adults are stout, very hard, wingless longicorns, wholly black or 

 shiny black or, less commonly, black with white markings. The dis- 

 tribution of the genus embraces the western half of the United States 

 as far north as Washington and Montana, and the whole of Mexico. 

 No species has been recorded from eastern United States, the West 

 Indies, or Central and South America. 



The number of species is uncertain, since both Casey and Psota 

 described many new forms whose specific validity is doubtful. During 

 the investigations 25 different species were encountered of which 9 

 proved new to science. Among other forms not noted by officers of the 

 Board, M. semipunctata and M. subrugosa, both from Baja, California, 

 are probably good species. 



The general habits of the various species are very similar. The adults 

 feed at night by chewing the margin of the segments, usually the 

 younger more succulent growth, or the fruit. During the day they 

 shelter in debris beneath the plants or in protected situations on the 



