XIX 



INSECTA : RHYNCOTA 



291 



Perhaps this very complicated life-history can be made 

 clearer by the following tabular summary. 



SUMMARY OF GENERATIONS OF CHERMES 



ON SPRUCE. ON LARCH. 



1st Generation Hibernating wingless 

 females which form 

 galls in the spring and 

 lay eggs. 



Winged females, leaving 

 galls in August. 



2nd Generation ! 



Some stay on spruce and Some migrate to larch 

 lay eggs in autumn. and lay eggs there in 



autumn. 



3rd Generation Hibernating females, like Hibernating females 

 Generation I. which lay eggs on 



larch in spring. 



4th Generation 



5th Generation 



Winged forms returning 

 to spruce and laying 

 eggs there in August. 



Wingless forms. 



Winged 



female and male. 



Eggs fertilised. 



6th Generation Hibernating females, 

 wingless, like Genera- 

 tion I. 



This insect Chermes is very undesirable in spruce and larch 

 plantations, not only because of the harm done by it to the 



