Teras terminalis. 75 



pierced not only the bark of the roots, but also the buds 

 and even the leaf-stalks. To be perfectly sure, I examined 

 the pricked buds and leaf-stalks; and found unmistakable 

 bored canals with the eggs in them. When the time of 

 gall formation arrived, towards the end of August, 

 I observed bright red galls growing out of one leaf 

 stalk, several buds, and some spots in the bark of the 

 root. They grew slowly; by the end of September 

 some of the root-galls were from '5 to i cm. in diameter, 

 but the bud and leaf-stalk galls were only the size 

 of a pea. In October these lost their brilliant red 

 colour, and dried up. The root-galls appeared at 

 first to pass the winter well, but finally perished, and 

 I did not succeed in obtaining a single fly. 



In July, 1878, I repeated the experiments, and 

 I obtained some bud-galls, and also some root-galls 

 which I brought to full development. In October the 

 growth of the galls ceased ; they were of soft, sappy 

 consistence, and the larvae were very small, but next 

 spring they came to their full growth, and began to get 

 woody. By an unlucky chance I obtained no flies from 

 these galls. This experiment was interesting, as it 

 confirmed my previous observation that Teras terminalis 

 pricks buds. To consider this as a mistaken instinct, 

 appears to me erroneous ; I rather incline to the view 

 that in the phenomenon we have a peculiarity trans- 

 mitted from the apterous generation. The two genera- 

 tions are so remarkably alike, that with the exception 

 of the presence of male flies in Teras terminalis no 

 distinction can be found, the female flies being exactly 

 similar ; and their close relationship is still further 



