HOMOPTERA 



435 



form all of which are wingless agamic females. This form (Fig. 507) 

 differs somewhat in appearance from the gallicolae. 



The migrants or sexuparce. — During the late simimer and fall there 

 are hatched from eggs laid by some individuals of the root-inhabiting 



Fig. 505. — Phylloxera, root-inhabiting form: a, shows a healthy root; b, one on 

 which the hce are working, representing the knots and swelhngs caused by 

 their punctures; c, a root that has been deserted by them, and where the rootlets 

 have commenced to decay; d, d, d, show how the lice are found on the larger 

 roots; e, agamic female nymph, dorsal view; /, same, ventral view; g, winged 

 agamic female, dorsal view; h, same, ventral view; i, magnified antenna of 

 winged insect; j, side view of the wingless agamic female, laying eggs on roots; 

 k, shows how the punctures of the lice cause the large roots to rot. (From 

 Riley.) 



form, young that develop into winged agamic females (Fig. 505, g, h). 

 These come forth from the ground, fly to neighboring vines, and 

 lay eggs in cracks in the bark or under loose bark. They lay only a 

 few eggs, from three to eight. 



