PEAR AND QUINCE INSECTS 



219 



in the creases of the bark, in old leaf scars and about the base 

 of the terminal buds. They are elongate pyriform in shape 

 and have a smooth shining surface. A short stalk at the larger 

 end attaches the egg to the bark and a long thread-like process 

 projects from the smaller end. A large proportion of the eggs 

 is laid before the buds open. They hatch in 11 to 30 days, 

 depending on the temperature. 



Most of the eggs have hatched by the time the petals fall. 

 The recently hatched nymphs are of a translucent yellow color 

 and are hardly visible to the unaided 

 eye, being scarcely -g^ inch in length. 

 They migrate at once to the axils of the 

 leaf petioles and stems of the forming 

 fruit, and when these places become 

 crowded they will scatter out on the 

 underside of the leaves and on the 

 petioles. They are provided with suck- 

 ing mouth parts and feed exclusively on 

 the sap. The larger part of the sap 

 taken into the body is elaborated into 

 a sweet, sticky substance known as 

 honey-dew, which is voided from the tip of the abdomen 

 and collects as a large glistening drop. The leaves and 

 fruit on infested trees are always more or less covered with 

 this unpleasant secretion and soon acquire a disgusting blackish 

 appearance from a sooty fungus which grows upon it. The 

 presence of the honey-dcnv is frequently the first indication that 

 the tree is infested. 



The psylla passes through five immature stages and acciuires 

 wings at the fifth molt (Fig. 202). About a month is required 

 for the complete life-cycle, and there are at least four broods a 

 season. The females of the later generations do not lay their 

 eggs on the bark, but deposit them along the midrib on the under- 

 side of the leaves or place them in the notches at the edge of 



Fig. 202. — The pear psylla, 

 last stage nymph. Enlarged. 



