ao Observations on Cynipidae, 



and shining; abdomen distinctly pedunculate. Legs 

 pale, only the coxae and bases of the femora dark. 

 The flies emerge at the end of May or beginning of 

 June. 



Experimental breeding. I observed these flies for 

 the first time on June 3, 1875, while they were busy in 

 the open air pricking the under sides of the tender oak 

 leaves. They are very delicate little flies, and can only 

 be kept alive for a few days, but it is not difficult to 

 observe them ovipositing if they are provided with very 

 tender leaves. They are first seen to move about 

 actively and examine the under surface of the leaves 

 carefull}^ with their antennae. They then direct the 

 point of the abdomen perpendicularly to the surface of 

 the leaf, the terebra is pushed into it, and an tgg glides 

 down into the channel thus pierced. This fly can 

 deposit a large number of eggs in the leaf in a short 

 space of time. The first traces of gall formation are 

 found at the end of three weeks as little hairy spots 

 which soon develop into the galls oi Neuroterus laevius- 

 cuhis. Of these there may be as many as 200 on 

 a single leaf. 



[Schenck's gall is found in May on Quercus sessiliflora and Q. pedun- 

 ctilata. 



Inquiline. Syncrgus apicalis.'] 



3. Neuroterus numismatis \ 01. 



Gall. Very pretty circular galls, like buttons 



covered with brown silk, with a shallow depression in 



the middle. Diameter, 2 mm. They mature in the 



autumn with the preceding {Neuroierus) gaU. (Fig. 3.) 



[} Cynips iiumtstnatis, Oliv. Neuroterus Rcauntun, Hartig.] 



