4 U.S. NATIONAL MUSEUM BULLETIN 25 6 



Cactaceae been studied as comprehensively as the prickly pears, it is 

 certain that the number of species of cactus insects, particularly among 

 the Lepidoptera, would have been increased materially. The Lepi- 

 doptera that have been reared from cacti other than Opuntia have 

 proved to be distinct species from those attacking prickly pears and 

 Cylindropuntias. 



A considerable amount of information has been secured concerning 

 the distribution, life history, and habits of many species, but in other 

 cases records are incomplete. 



The family Cactaceae, being a very distinct plant group v^ith peculiar 

 characteristics of growth and habit, has its own insect fauna. One finds 

 not only species but whole genera and even groups of genera that, 

 so far as is known, are restricted to prickly pears and other types of 

 cactus plants. Almost without exception those insects which are 

 primarily cactus feeders do not attack other plants. Furthermore, 

 insects which are general feeders rarely turn their attention to 

 Cactaceae; this statement is generally true even of omnivorous in- 

 sects such as grasshoppers. 



The prickly-pear pest in Australia flourished unchecked by native 

 insects or by introduced insects of polyphagous habits; there are only 

 a few records of incidental feeders. 



And within the Cactaceae there is a considerable degree of host 

 restriction, especially among the Lepidoptera. This host restriction 

 is rarely specific, however, but is confined to plants of the same type. 

 Thus, the moth borers infesting prickly pears may attack most species 

 of Platyopuntia in their range of distribution, but they do not attack the 

 Cylindropuntias. Similarly the phycitid borers of such cactus types 

 as Echinocactus and Echinocereus have not been recorded from either 

 Platyopuntias or Cylindropuntias. On the other hand, the Argentine 

 phycitid fruit enemy Ozarnia hemilutella Dyar feeds in Cereus as well as 

 in Opuntia fruit. 



Among the Coleoptera, members of the genus Moneilema Say feed 

 mainly on Opuntia; various species attack both Platyopuntias and 

 Cylindropuntias in the same district and occasionally they have been 

 recorded from other cactus hosts. Most of the Gerstaeckeria Champion 

 weevils seem to be confined to prickly pears, but one species is an 

 enemy of Cylindropuntias. The Cactophagus LeConte weevils attack 

 the prickly pears Nopalea and Cereus, but have not been found in 

 Cylindropuntias. 



The coreid bugs of the genus Chelinidea Uhler are Opuntia feeders, 

 generally attacking both prickly pear and cylindrical forms, but one 

 species seems to be restricted to Cylindropuntias. The other coreid 

 genera Narnia StSl and Leptoglossus Guerin Meneville, are inclined 

 to pierce the fruit of various Cactaceae. 



