28 BRITISH OAK GALLS. 



oviposition — seldom or frequent, as the case may be 

 — is carried out with remarkable certainty in the 

 right part of the plant. As is shown on another 

 page, error of judgment means the loss of progeny. 



The study of the imagines will be found very 

 puzzling to the general entomologist, as there is a 

 very general likeness amongst the species. The 

 inquilines, especially, greatly reseml^le the true gall 

 producers. 



The bodies of the Cynipida3 are of very beautiful 

 and bright metallic colours. Red, green, orange and 

 blue predominate. The Avings also are exceptionally 

 iridescent. The imago of (J. KoJlari is the prettiest, 

 having a j^right metallic yellow, orange and purple 

 body, and highly iridescent wings. All the species 

 are small, varying from 2 mm. to 5 mm. in length. 

 Many are very agile, and all are graceful in their 

 movements. 



They have four wings. The two antei'ior wings are 

 al^out the same lengtli as the body; the other two are 

 about half the size ; the margins are usually fringed 

 with minute hairlets. Some species are wingless. 



The antenna are long in comparison with the size 

 of the insect. In the males there are generally one or 

 two joints more than in the females ; they are also 

 thinner. 



The abdomen of the male is differently shaped from 

 that of the female, but there is no difference in the 

 coloration of the sexes. Tlie difference in the size 

 and form of the ovipositor depends upon the genera- 

 tion of the insect. In those species which appear 

 in the spring it is much shorter and less curved than 

 that possessed by those which oviposit in the autumn. 

 The process of egg-la3dng on the part of gall producers 

 is somewhat complicated; it is therefore necessary that 

 the instrument w^ith which it is performed should be 

 elaborate. It is known as the terebra, or ovipositor. 

 It consists of three portions : the seta, and two 

 serrated spicule. When at rest the entire instrument 



