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 resemble the true gall 
producers. 
The bodies of the Cynipide are of very beautiful 
and bright metallic colours. Red, green, orange and 
blue predominate. The wings also are exceptionally 
iridescent. The imago of C. Kollari is the prettiest, 
having a bright 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 anterior wings are 
about the same length as the body; the other two are 
about half the size; the margins are usually fringed 
with minute hairlets. Some species are wingless. 
The antenne 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. The 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-laying on the part of gall producers 
is somewhat complicated ; it is therefore necessary that 
the instrument with 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 
