﻿Heicropieva of Cnuihcrnj Lake Region 



89 



forcible action will ordinarily dislodge them. The adults are 

 almost equally difficult to move (possibly the basis for Walker's 

 name stupida), no doubt having become fully adapted to depend- 

 ence on their protective features to escape enemies. The human 

 enemy is, of course, an entirely negligible factor in the immense 

 solitudes of the great birch forests and especially in the tree tops, 

 but the prying eyes of insectivorous birds may well be deceived 

 by the perfection of the resemblance displayed. 



The attraction for the ants lies in the liquid discharge from 

 the anus, no doubt comparable to the " honey dew " of aphids, 

 and the constancy of the association would indicate that the ants 

 make a large use of this food supply during the period of life of 

 the tree-hoppers. When aphids are also present the same ants 

 appear to visit either aphid or tree-hopper. 



The species was first described by Walker from specimens 

 received from Canada (?) but with no description of early stages. 

 Later descriptions by Butler, Provancher and Goding, none of 



Fig. 37.- — Yellow bircli twigs showing egg-piinetures (two, three 

 and four years old) of Varynota sfiipida Walk. Photo by Fivaz. 



