10 



states. It was apparently introduced into Connecticut early in 

 the present century; since then it has spread west to Ohio, 

 Michigan, and Illinois, south to New York and New Jersey, 

 and probably over much of New England, though here it has 

 been reported as destructive only in Massachusetts and Con- 

 necticut. 



The adult pear psylla is a small, jumping 

 louse about one tenth of an inch long, resem- 

 bling, when magnified. Fig. 3. It has four 

 nearly transparent wings, and is reddish with 

 n transverse dark stripes on the abdomen. 

 There are two distinct forms. The summer 

 broods are much lighter in color than the 

 brood which passes through the winter. This 

 difference is so great that the two forms were 



„ ^ „ considered distinct species until the life his- 

 T^iG. 3. Pear Psylla. 



Magnified. tory was carefully worked out by Mr. M. V. 



Slingerland. 



The dark form passes through the winter in some sheltered 

 situation about the tree, such as beneath loose bark, or in the 

 crevices between the branches. In early spring they come forth 

 from their hiding places and deposit their eggs about the buds 

 and on rough bark. These eggs are very small, and of the 

 extraordinary form represented in Fig. 4. When first deposited 

 they are yellowish, but turn dark soon afterwards. The eggs 

 hatch in three or four weeks, the time depending largely on 

 weather conditions. The young psyllas, which during their 

 immature stages are called nymphs, crawl to the stalks of the 

 unfolding leaves, in which they insert their tiny beaks to suck 

 out the sap. They grow rapidly, occasionally moulting or shed- 

 ding their skins to provide for their increase in size, and in the 

 course of a month become mature. 



The first summer brood thus developed deposits eggs on the 

 under sides of the leaves. These eggs hatch 

 ten days later, and mature in about three 

 weeks. The insects of the second brood 

 suck the sap from the leaves. There are ^"^- 4- Kgg. Magnified, 

 several of these summer broods, the number varying with the 



