58 



FOURTH ANNUAL REPORT OP 



facts sufficiently attest the identity of the two ty23es, and we have here 

 another case of an insect possessing two distinct habits. It is also like 

 many others of its Farail}^, polymorphic, /. e., it exists in different forms j 

 yet we have to do with but one si)ecies. 



FURTHER FACTS RESPECTING THE HABITS OF THE ROOT-INHABITING TYPE. 



The 3^oung hatched from the eggs on the roots are absolutely undis- 

 tinguishable from those hatched in the galls; and the gravid apterous female 

 differs in no respect whatever from the mother gall-louse. There is, how- 

 ever, a different egg-depositing form, which, as it moults, becomes tubcrcled, 

 and more elongated or pear-shaped, as shown at Figure 28, j. Some of 

 these tubercled individuals remain without wings, while others secm'to be 



[Fig. 28.] 



P:xplanation- of FiauuE 2S.— (/, shows .a healthy root; b, one on which tlie lice are working, 

 representing the knots and swellings caused by their punctures; r, a root that has been deserted by 

 them, and where the rootlets have commenced to (tecay; d, d, d, shows how the lice are found on the 

 larger roots; e, female pupa, dorsal view; /, same, ventral view; g, winged female, dorsal view; h, 

 same, ventral view; i, magnified antenna of winged insect; j, side view of the wingless female, lay- 

 ing eggs on roots; it, shows how the punctures of the lice cause the larger roots to \'ot. 



