INSECTS INFESTING THE PEAR TREE. 119 



insect as a pest of the cherry tree, but in this state it does most 

 injury to the pear ; therefore, it is placed in the list of pear 

 insects. 



The pear slug is found in many orchards in Central Cali- 

 fornia ; it feeds upon the foliage of the pear, the cherry, and 

 the plum tree, but only eats the epidermis off of the upper side 

 of the leaves, leaAdng the framework and under surface 

 untouched. 



" The trees attacked by them are forced to throw out new 

 leaves during the heat of the Summer at the end of the twigs 

 and branches that still remain alive ; and this unseasonable 

 foliage, which should not have appeared until the next Spring 

 exhausts the vigor of the trees and cuts off the prospect of 

 fruit." — Harris. 



The egg is deposited in a cut made in the leaf, by the saw- 

 like apparatus or ovipositor of the female. Nineteen eggs have 

 been found deposited in one leaf. 



The larva (Fig. 96) is hatched from the egg in two days, and 

 feeds upon the leaves, as described above ; it attains its full 

 growth in from twenty to twenty-five days. During the time 

 it is feeding it exudes an olive-colored slimy substance, which 

 covers the body and gives it the appearance of a tadpole. 

 When it ceases eating it casts its skin and slimy coat, and 

 appears with a clean, yellowish skin ; the divisions of the 

 segments of the body are plainly seen ; it then descends to the 

 earth and crawls beneath the surface, from one to four inches, 

 and forms a cocoon, where it undergoes its metamorphoses or 

 changes ; in about fifteen days the perfect insect (Fig. 97) 

 appears. 



Fig. 96. 



Fig. 97. 



Fig. 96. — Pear Slug ; an infested leaf on which are two slugs ; 

 above it is one of the slugs, enlarged — color, olive-brown. 

 Fig. 97. — Pear-Slug Saw-fly, enlarged — color, black. 

 The first brood appears late in April, or early in May ; the 



