Dryophanta divisa. 67 



happen that they grow out of the buds of last year's 

 shoots, and then they are not unfrequently formed on 

 the trunk of the tree. 



That the two species of Dryophanta just described 

 should both seek the little adventitious buds at the 

 foot of the oak, is probably due to the fact that these 

 buds are the first to be reached in spring by the rising 

 sap, and therefore they are able to support gall forma- 

 tion while the higher buds are still dormant. It is of 

 advantage to the summer generations of Dryophanta 

 that their flies should be enabled to leave the galls as 

 early as possible, since by doing so they are the 

 sooner safe from the attacks of parasites. The flies 

 emerge from SpatJicgaster stmilis galls in May, almost 

 a fortnight earlier than from SpatJicgaster Taschcnbcrgi 

 galls. 



Fly. 2 mm. long ; black, sufficiently like Spathegaster 

 Taschenhergi to be confused with it, and only to be 

 distinguished from it by the darker colouring of the 

 legs ; these are dark yellow, the outer margins of the 

 femora and tibiae black. 



[The green velvet bud-gall is found on dormant buds of Oucrcus 

 pedunculata in April.] 



16. Dryophanta divisa \ 



Gall. Of the size of a buckshot ; several are usually 

 found together on the under side of the leaves, springing 

 from the veins of the leaf; at first of a bright red 

 colour but this at maturity passes into a brown. The 



\} Cynips divisa, Hartig.] 

 F 2 



