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

 surface of the leaf, in which the egg is deposited, as shown in Fig. 

 497. The egg hatches in about two weeks and the little larva 

 makes its way out of the cell through a crescent-shaped cut. 



The young larva is at first nearly white, except the yellowish- 

 brown head, but very soon a slimy or gluey olive-colored liquid 

 exudes from over the entire body, giving it the appearance of a 

 minute slug, from which it gets its name. The head is now dark 

 brown, appearing almost black under the slime, and the body is 

 also darker. The anterior segments are much swollen, concealing 

 the head and the thoracic legs. The abdomen is furnished with 



FIG. 497. Illustrating method of oviposition and emergence of the pear 

 ' slug: a, cutting of cell beneath epidermis, showing the tip of the ovi- 

 positor; 6, the cell after the egg has been deposited; c, same after 

 escape of the larva all much enlarged. (After Marlatt U. S. Dept. Agr.) 



seven pairs of prolegs, the usual pair on the last segment being 

 wanting so that the tip of the abdomen is slightly elevated. The 

 little slugs commence eating out small bits of the upper surface 

 of the leaf, which they gradually enlarge until nearly the whole 

 upper surface is denuded, leaving merely a network of veins, 

 held together by the brown epidermis of the lower surface, which 

 is nearly intact. Leaves thus injured turn brown, die and drop^ 

 so that a tree will sometimes be nearly defoliated, except for the 

 new growth which starts out. The larvae grow rapidly, becoming 

 full grown in about twenty-five days, when they are about one- 



