CURRANT AND GOOSEBERRY INSECTS 



851 



merous progeny. Through- 

 out the summer only fe- 

 males (Fig. 311) are pro- 

 duced, and the young are 

 born ahve. At first nearly 

 all of the lic(^ are wingless, 

 but as the leaves become 

 crowded, winged females 

 develop and migrate to 

 other bushes. 



The lice become al^un- 

 dant ])y the middle of 

 May in New York, and 



often cover the entire under surface of the leaves (Fig. 313). 

 The irritation of their combined punctures causes the leaf 



. 311. — Th(» currant phint-luusc, wiiii?- 

 less viviparous female HularKctl. 



Fig. 812. — Currant leaves curled by i>lant-lice. 



to become badly curled and distorted so that pocket-like 

 cavities are formed on the under side (Fig. 312). The upper 



