The Jumping Plant-Lice or Flea-Lice 



Fig. 155. — Pear-tree Psylla: a, egg; 



b, larva — both greatly enlarged. 



(After Marlatt.J 



the large wing pads. Its color is then dark reddish brown. 



In all the early stages the in- 

 sect is broad-oval and very 

 much flattened, resembling 

 more nearly some scale in- 

 sect rather than a perfect 

 flea-louse. It is also slug- 

 gish in these early stages. 

 When the nymph casts its 

 last skin the adult insect 

 emerges. It resembles much 

 more closely a minute 

 cicada or harvest-fly than 

 any other homopterous in- 

 sect. It hibernates in the 



adult stage in crevices in the bark of pear-trees and emerges 



with the first warm spring 



days, beginning with the 



laying of the eggs on the 



leaves before they have 



fully expanded or even 



placing them in cracks 



in the bark on the twigs. 



The larvae hatch in ten to 



seventeen days and station 



themselves on the surface 



of the leaves or on the 



leaf petioles. There are 



four or five generations 



each summer in Mary- 

 land but fewer farther 



north. 



Fig. 1 56. — Pear-tree Psylla : pupa. 

 (After Marlatt.J 



261 



