HTMENOPTBRA. 189 



ichneumon-flies are an important agent in keeping down 

 injurious insects. 



FIG. 90. Ichneumon-fly, enlarged. From Riley. 



The ants are possibly the most interesting of all insects. 

 They are true communists. In them, as in the white 

 ants (p. ), there is a differentiation of the individuals 

 into males, females, and workers, the latter being wingless. 

 A.ny adequate treatment of these forms would of itself 

 demand a book larger than this volume. The males and 

 females take " wedding-flights," after which the male soon 

 dies, while the females bite off their wings and henceforth 

 have nothing to do except to lay eggs. These eggs are 



