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 horn 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 Seszas, 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 living, like the grub of the beetle-borers, in 
the wood; some hollowing out branchlets along the pith, 
others, like the peach-borer, living between bark and wood 
a little below the ground; others bore in plum, pear, maple, 
grapevines. 
The same remedies used in the case of other borers are 
to be applied, namely, cutting out the culprit or preventing 
its ingress by applications of lime wash, dendrolene, etc. 
Spinners are typical moths, of medium size, brightly 
colored, generally white, yellow, brown, gray, or black; 
flying 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 live within the plant or 
ground, hairy, bristly, 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 larve living 
