CHAPTER IV. 
THE CYNIPIDZ AFFECTING THE OAK. 
Since the Cynipide are such interesting and remark- 
able insects, a few pages will be devoted to a very 
brief description of the imagines and their early stages. 
More than a mere outline of these facts is not desir- 
able, since the present volume is designed to treat of 
the galls they produce; nor, indeed, is it possible to do 
this much without quoting largely from two works 
frequently mentioned in previous and subsequent pages, 
both of which works contain exhaustive and detailed 
information concerning these gall-wasps. There is 
practically no feature of great importance that can be 
added. 
But there may be many collectors, students, and also 
readers who have not access to other works on the 
subject of oak gall producers, and they would welcome 
some information concerning the Cynipide. For their 
assistance this chapter is inserted. 
The name of Cynipide was given to this group of 
the aculeate Hymenoptera by Linneus. 
They are very interesting insects in several ways. 
Almost all of them are either gall producers or are 
parasitic upon other insects. The distinguishing 
features of the family, according to Cameron (‘ Brit. 
Phyto. Hymen.,’ vol. ii, p. 142), are shown in eleven 
particulars, an important one being that the 
abdomen is petiolated and laterally compressed. 
The imago has many points of great interest. So 
