INSECT ENEMIES. 



117 



appearance in the larva state. The name Blennocampa 

 signifies a slimy caterpillar. Its favorite trees are the 

 pear, cherry, and quince, and it is sometimes found on 

 the plum and mountain ash. Ordinarily there are but 

 few on a leaf, but sometimes the leaves are fairly spotted 

 with them. Thirty have been counted on a single leaf. 

 Professor Peck, of Massachusetts, wrote its natural history 

 in 1790 with such critical accuracy that little has been 

 since added to our knowledge of its life history. It is 

 now quite generally spread over the country. This slug 

 comes from the eggs of a saw-fly, about one-fifth of an 

 inch long, resembling the common house-fly. Its body 

 is glossy black. The first two pairs of legs are clay- 



Fig. 104. Female. 



Fig. 105. Larva. 



PEAR-TREE SLUG. 



colored, with dark thighs. The hind legs are dull black 

 with clay-colored knees. The wings are transparent, 

 slightly convex, and uneven on the upper side, with 

 brownish veins. They reflect the changeable colors of 

 the rainbow, with a smoky tinge in a band across the 

 middle of the first pair. 



The female is provided with a saw-like appendage, 

 with which she cuts a curved incision through the skin 

 of the leaf, in which she lays her eggs singly, and gener- 

 ally on the under side, from about the middle of May 

 into June. In fourteen days they begin to hatch. At 

 first the slugs are white ; but soon a slimy matter oozes 

 through the skin, and covers their backs and sides with an 

 olive-colored, sticky coat. The head is small, of a dark 



