ORCHARD INSECTS 



317 



recognized by the browning of the leaves of pear and cherry, 

 or sometimes plum, where it has eaten off the surface of the 

 leaves. 



The parent insect is a small saw-fly, about one-fifth of an 

 inch long, glossy black, with four iridescent wings, crossed 

 by a smoky band at the middle and folded over the back 

 when at rest. The flies appear by the time the foliage is 

 well out, by mid-April in Maryland and late May or early 



FIG. 231. The pear slug (Caliroa cerasi Linn.). (After Marlatt, 

 U. S. Dept. Agr.) 



a, adult female saw-fly; b, larva with slime removed; c, same in normal state; 

 d, leaves with larvae natural size; a, b, c, much enlarged. 



June in Iowa and New England. Like other saw-flies, the 

 female has a strong ovipositor with saw-like teeth at the 

 tip, with which she cuts a little blister-like cell beneath the 

 upper surface of the leaf, in which the egg is deposited 

 (Fig. 232). 



The bodies of the half-grown larvae are dark blackish- 

 green, covered with a viscid, slimy substance which has 

 given them the name of slugs. The head is dark brown, and 



