130 DISEASES OF THE SWEET PEA 



a reddish fluid secreted by the thrips. As 

 these drops dry they gradually turn black. 

 As the attack progresses, the leaves lose 

 all their green color, become limp, and 

 drop off. 



Life History of Thrips. An adult 

 thrip is about one-twenty-fourth of an inch 

 in length, and is dark brown in color, with 

 the tip of the body somewhat lighter. The 

 female deposits her eggs within the leaf 

 tissue, and these hatch after about eight 

 days. The young larvae feed in the same 

 way as the adults, but it is the young 

 which in feeding exude the reddish drops 

 previously mentioned. In reaching full 

 growth the larvae undergo two resting 

 stages — ^prepupa and pupa, during which 

 they take no food and remain motionless. 

 Twenty to thirty days after the eggs have 

 hatched the adult is ready for reproduc- 

 tion (figs. 20a to c) . 



