28 Observations on Cynipidae. 



II. Aphilotrix Group. 



The genus Aphilotrix includes a large number of 

 gall-flies among which I have been able to establish 

 a similar alternation of generations. Like Neuro- 

 terns the genus Aphilotrix is found only in the female 

 sex. 



5. Aphilotrix radicis. Fbr.^ 



Gall. The gall is many-chambered, occurs on the 

 roots and lower part of the trunks and varies in size 

 from a cherry to a man's fist. At first the gall is pale, 

 almost pure white when formed underground and 

 excluded from the light, and in consistence it resembles 

 a potato. Later it becomes brown and woody until it 

 is perfectly hard especially at its base. When it 

 reaches maturity the upper surface has a fissured and 

 uneven appearance and is of a brownish or black 

 colour. On section it shows innumerable round larva 

 chambers. (Fig. 5.) 



Bearing the Fly. The mature galls which are found 

 in the autumn are collected and kept through the 

 winter in a cool place. The flies are perfectly developed 

 in autumn, as may be proved by opening some of the 

 cells, but they winter in the gall and do not emerge 

 until the following spring, about the end of April or 

 beginning of May. 



Fly. Size, 5-6 mm. ; reddish brown ; the mesonotum 

 is marked by three darker longitudinal stripes, one 

 median and two lateral, and there is also a transverse 



[' Cynips radicis^ Fbr. Andricus radicis, Mayr.] 



