POLYMORPHISM. 



S 9 



many other insects, which made its appearance among the solitary 

 species, like the Tenthredinidae and Cynipidae, long before the develop- 

 ment of social life. Moreover, polymorphism may occur in male in- 

 sects which, of course, are not parthenogenetic. That parthenogenesis 

 is intimately connected with sexual dimorphism, at least among the 



FIG. 52. Phcidolc instabilis. (Original.) a. Soldier ; b-e. intermediate worker? 

 /, typical worker (micrergate) ; g, dealated female; /;. male. 



