158 Control of Parasites 



pointed wings, the front pair much longer than the hind 

 wings; the large caterpillars are hairless and peculiarly 

 marked by a hard, glossy eye spot or a curved liorn on the 

 last segment. The ash-tree sphinx and the pine sphinx are 

 examples of this family. Their size and usually rare, single 

 occurrence makes their damage ordinarily not worth con- 

 sidering. Where unusually developed, collecting is prob- 

 ably the readiest remedy. 



Allied to this group are the Sesias, with clear wings like 

 hornets, whose caterpillars attack many cultivated plants 

 and become quite injurious, especially to young trees. 

 Willows, poplars, birches, and alders are attacked by them. 

 They are borers, often confounded with the beetle-borers, 

 the caterpillar li\'ing, Hke the grub of the beetle-borers, in 

 the wood; some hollowing out branchlets along the pith, 

 others, Hke the peach-borer, living between bark and wood 

 a httle below the ground; others bore in plum, pear, maple, 

 grapexines. 



The same remedies used in the case of other borers are 

 to be applied, namely, cutting out the culprit or preventing 

 its ingress by appUcations of Ume wash, dendrolene, etc. 



Spinners are typical moths, of medium size, brightly 

 colored, generally white, yellow, brown, gray, or black; 

 fl\ing at night; the caterpillars, which in some cases live 

 for several years and, as a rule, at least winter as such, are, 

 with the exception of those who hve within the plant or 

 ground, hairy, brisdy, or warty, and vividly colored; they 

 have a pronounced capacity for spinning and pupate in silk 

 cocoons: the silkworms belong here. 



Being chiefly gregarious, they are much more destructive 

 than the former group, and, indeed, some of the most injuri- 

 ous pests are to be found among them. A few are wood- 

 borers, the very large whitish and black-spotted larva? hving 



