X. 



In regard to the Coleoptera, the following are capable of causing damage 

 to prickly-pear :— The various species of Moneilema, Ccenopceus, and Gers- 

 tceckeria. 



The adult of Moneilema is a large black wingless longicorn beetle, which 

 feeds gregariously on the young segments of the host plant, while the larva is 

 a large grub living in tunnels hollowed out by it in the stems and joints. Monei- 

 lema is widely distributed in the drier parts of the United States and Mexico. 



Ccenopceus is also a large longicorn with similar habits, its home being 

 Southern California and the adjacent regions. 



The various cactus weevils, Qerstceckeria, spp. with the exception of G. 

 hubbardi, do comparatively little damage to the joints, either in the larval or 

 adult stages, though the injuries caused by the larva while feeding within the 

 segments, may sometimes become the seat of secondary infection by micro- 

 organisms and certain scavenging flies. G. hubbardi was found to be usually 

 associated with a very destructive moth, Melitara prodenialis, in its attacks 

 on prickly-pear in Florida. 



The lepidopterous enemies comprise a number of cactus moth borers, 

 belonging to the Phycitidce, found in North and South America and in the 

 West Indies, as well as certain others, such as Mimorista and Marmara, found 

 especially in North America and the West Indies. 



The Phycitid enemies include the very destructive cactus moths belonging 

 to the genus Melitara, found in the United States, Mexico, and the West Indies, 

 and also certain moths, Zophodia, spp., occurring in Argentina and Uruguay, 

 in South America. 



The caterpillars of these insects live within the joints of the plant, and 

 cause great destruction, partly on account of their eating out the tissues and 

 partly on account of the rapidity with which attacked segments become invaded 

 by secondary organisms, such as bacteria, fungi, and scavenging flies. The 

 death of infected joints, and even plants, is a quite common result. 



Mimorista causes a great destruction of young segments of prickly-pear, 

 and therefore acts as an important agent in controlling the spread of this group 

 of plants. This insect, or insects producing a similar effect, occur in Texas, 

 the West Indies, in Brazil, and, no doubt, in Mexico also. 



Marmara, whose tiny caterpillar is a " leaf -miner " causes very little 

 injury as a rule, though sometimes secondary invasions may be serious. 



Amongst the Hemiptera are certain prickly-pear enemies, especially 

 the various species of wild cochineal insects, and the members of the genera 

 Ghelinidea and Narnia. These all more or less injure the species with which 

 they are associated. There are also others, such as various Aphids and scale 

 insects [Diaspis), but they are not of much importance, as a rule, in controlling 

 or destroying Opuntias. 



The wfld cochineal insects found attacking prickly-pear in India, Ceylon, 

 and South Africa have already been referred to. Those seen in the United States, 

 West Indies, Brazil, and Argentina had very little effect on their host plants! 

 This might be accounted for in great measure by the presence of parasites. 

 It is known that some of them, e.g., the true cochineal, and certain wild cochineals, 

 cause very little injury by feeding, whereas others, e.g., those in Ceylon, India' 

 South Africa, and some in Mexico, cause serious constitutional disturbances 

 which may result in the death of the affected plant. 



The " Cactus bugs " Ghelinidea and Narnia attack the joints and fruit 

 respectively, and are regarded as being very serious enemies of prickly-pear 

 They are found in the United States, Mexico, and the West Indies, and related 

 forms occur in Brazil. 



