6 4 INSECTS 



the vast majority are soft, naked, slug-like creatures, 

 similar to those of the potato beetle, or only scantily 

 clothed like those of the elm leaf beetle, there are some 

 that are more slender, white, and worm-like, mining 

 in stems, leaves or even roots, and making more or 

 less characteristic galleries, channels or chambers. 

 They may be only surface channels like those made 

 on cucurbs by certain species of Diabrotica; they may 

 be real borings like those made in root tissue by some 

 flea beetles; or they may be mines in leaf tissue, like 

 those made by some of the species of Hispids. It is 

 rare that the attack of a Chrysomelid really threatens 

 the life of a plant, though there are exceptions to this; 

 the grape-vine root- worm for instance, and other 

 root-feeders. 



In the long-horned beetles, or CerambycidcB, the 

 adults do very little feeding; but the larvae are borers 

 in woody tissue or in stems of plants, differing from 

 those of the Buprestids by being more cylindrical 

 and with a less prominently dilated anterior portion. 

 They are known as round-headed borers as distin- 

 guished from the flat-headed kind already described, 

 and their galleries in section are nearly round instead 

 of transversely oval. As a rule, also, they are more gen- 

 erally borers in heart-wood and do not make the irreg- 

 ular shallow galleries under bark that are so char- 

 acteristic of the flat-headed types. There is no part 

 of a tree that is exempt from their attacks: from the 

 roots to the very tips of the twigs it may be in- 

 fested, and they do not confine themselves to sick or 

 dying trees either: a perfectly sound tree is just as 

 likely to be attacked as any other and, indeed, some 

 species are found in sound trees only. There are many 

 interesting points connected with the development 

 of these borers, the life period of some of them being 



