Usually before placing the egg the tly runs about rapidly over the 

 uppei- surfa(;e of the leaf, examining it carefully, aiul then goes over to 

 the under side to insert an egg, after which she reappears on the upper 

 surface of the leaf and rests for a minute or so before tlying to another 

 leaf. 



It often happens that a good many eggs are deposited in a single 

 leaf, but I am convinced that this is usually by different flies or at 

 different visits by the same individual. The loosened epidermis about 

 the egg dries somewhat, and the egg-cell soon appears as a minute 

 brownish spot with the almost colorless egg showing at the center. 

 The egg is oval, slightly flattened on one side, and remains in its 

 peculiar cell (see fig. 2, h) for a period of about two weeks before the 

 larva escapes. It is so placed in the leaf that it can be readily watched 

 and its gradual increase in size by absorption from 

 the leaf and the development of the young larva 

 can be easily studied with a hand lens. 



The larva, emerges on the upper surface of the 

 -f leaf through a ver.y regular semicircular cut 

 which it makes near the center of the cell. At 

 fii'st it is clear or free from slime and in color 

 nearly white, except the yellowish-brown head ; 

 but almost immediatel}'^ the slimj' or gluey olive- 

 colored liquid begins to exude over its entire 

 body, giving it the appearance of a minute slug, 



Fi(i. o.— Pear slik; : a, last .., -i i- i • i -i x -j. tx 



moulted larval skin: /..larva O^ ^^^^ SUail, irom whlch it gets itS name. ItS 



after casting last skin- head is dark brown, appearing black under the 



somewhat enlarged (orig- ,. i ^i i i i i i j. n 



ijjj^i) slime, and the bod^^ also becomes almost equally 



dark. The anterior segments are much swollen, 

 covering up and concealing the head and thoracic legs. In common with 

 other saw-flj^ larva? it lias a great number of false legs or prolegs on the 

 abdominal segments; in this species there are fourteen such prolegs, the 

 terminal pair being wanting, and the tapering tip of the l)ody is usually 

 slightly elevated. 



As soon as the larva emerges from the egg it begins feeding on the 

 upper surface of the leaf, eating out small lioles or patches al)Out the 

 size of a pin head or smaller, but never eating entirely through the leaf. 

 Tlie larva" feed almost invariably on the upper side of the leaves and 

 the minute eaten spots which the}' make at the start rapidlj? increase in 

 size until much of it, but not the entire surface of the leaf, is denuded, 

 leaving merely a network of veins, or a leaf skeleton, held together bj' 

 a nearly intact lower epidermis. Leaves thus eaten turn brown, die, 

 and fall to the ground, the tree being frequently defoliated, except for 

 l.he effort it usually makes to put out a new growth. 



The characteristic features of the larva are its swollen anterior seg- 



