CACTUS-FEEDING INSECTS AND MITES 89 



The usual host plants are Opuntia imbricata in Texas and New Mexico, 

 0. sptnosior in New Mexico and Arizona, and 0. bernardina in California. 

 In the vicinity of Tucson, Arizona, 0. spinosior was the favoured host 

 plant; other Cylindropuntias such as 0. fulgida and 0. versicolor were 

 selected more rarely. Platyopuntias do not appear to be attacked in the 

 field. However, the adults fed readily on Opuntia lindheimeri in cages, 

 while young larvae, transferred in August into segments of this prickly 

 pear from 0. imbricata, developed successfully in lindheimeri segments and 

 produced adults the following June. 



There is one generation annually. The beetles emerge from late May 

 to July and live for 3 to 4 weeks; adults have not been observed in the 

 field later than July. The narrowly elliptical eggs are deposited singly 

 beneath a gummy secretion on the broken surface of segments where 

 the adults have been feeding. The larvae tunnel in the stems and 

 branches, and pupate within the galleries in April and May. 



On various occasions heavy infestations of lai-vae have been reported 

 in fields of 0. imbricata, 0. spinosior, and 0. bernardina. The laige plants 

 are considerably damaged through the death of infested stems, but are 

 rarely destroyed completely. Small plants may be killed outright; for 

 example, in an area of stunted 0. imbricata at Shafter, Texas, a very 

 definite proportion of the plants was destroyed by this insect. 



ARCHLAGOCHEIRUS Dillon 



The one cactus feeding member of the genus, A. funestus (Thomson), 

 formerly placed in Lagochirus Erichson, appears to be restricted to 

 prickly pears. Special investigations conducted by the Board in Mexico 

 failed to locate other host plants. 



Archlagocheirus funestus (Thomson) 



This rather large broad longicorn, attaining a length of a little more 

 than an inch, is dark brown in color with a marbling of darker markings. 

 Its known distribution is the southern half of Mexico, where it has been 

 found around Puebla, at Cuernavaca and other points in the State of 

 Morelos, at Chilpancingo in the State of Guerrero, and at Oaxaca. 

 The host plants are robust pi ickly pears with thick stems and branches 

 of the tree and semi-tree pear groups, such as Opuntia tomentosa, 0. 

 lasiacantha, 0. streptacantha, 0. hyptiacantha, and Nopalea cochenillifera. 

 The smaller shrubby forms of prickly pear appear to be avoided, 

 although under cage conditions in Australia the insect has completed 

 its life cycle on 0. inermis. 



Attention was paid to its life history during 1934-35 in the State of 

 Morelos, where it was rather prevalent in local areas, more especially 



