CACTUS-FEEDING ESTSECTS AND MITES 71 



Brazil. The larvae, which varied in color from light blue to green-blue, 

 appeared to be about half-grown and had excavated rather large 

 cells which were typical of the work of the Tapia larvae. The more 

 succulent segments were favored, and young plants occasionally were 

 killed by their activity. Adults were not reared. 



Parasites. — A dead larva from Porto Alegre produced braconid para- 

 sites Apanteles sp. 



CACTOBROSIS Dyar 



Of the five species from the United States and Mexico included in this 

 genus by Heinrich (1956), the three Mexican forms, Cactobrosis longi- 

 pennella (Hampson), C. maculifera Dyar, and C. insignatella Dyar, are 

 known only from collected adults. He gives Ferocactus as the probable 

 food plant of C longipennella. 



Cactobrosis femaldialis {Hulst) 



During the Board's investigations this insect was located in the general 

 vicinity of Tucson, Arizona, the host plant being the barrel cactus 

 Ferocactus wislizenii. Heinrich lists many localities in the more southern 

 section of Arizona, as well as San Diego, California, the moths having 

 emerged or been captured in every month from April to November. 

 He states that one specimen is labeled as having been reared from 

 Peniocereus greggii which differs very greatly in its habit of growth from 

 Ferocactus. In 1 899 H. G. Hubbard recorded the rearing of moths from 

 larvae feeding in decaying pulp of the giant cactus Carnegiea gigantea. 

 The Board's officers were unable to find larvae in this host; however, 

 solitary larvae of a dull-blue color were discovered in the giant cactus, 

 but no adult was reared. As the larvae of Cactobrosis fernoldialis are 

 gregarious, the solitary larvae in Carnegiea presumably represent a 

 different insect. 



As many as 100 larvae have been counted in one plant of F. wisli- 

 Zeni. Their presence is indicated by the yellowish appearance of a 

 portion of the plant. They tunnel freely, discharging excrement 

 through a few small holes. Often the outer husk of the plant remains 

 alive, the interior becoming a semiliquid mass of rotting pulp in which 

 dipterous and other scavenger larvae breed in great numbers. In the 

 final stage of destruction the plant is reduced to a dry hollow shell. 

 Rather flimsy cocoons of light texture are spun beneath the plant 

 or in adjacent debris. Cocoons collected in June produced adults 

 late in the same month. 



The adult has a wing expanse of 34 to 55 mm.; the forewings are 

 grey with darker markings and suffusions; the hindwings are white 

 partially shaded with pale fuscous. 



