THE CYNIPSID. 181 
considerable number of eggs. When the puncture is made the 
insect spreads a secretion over the wound which is of a very 
irritating character, and it is believed to excite the nutrition of 
the vegetable tissue to develop irregular masses of its cellular 
structures. There are multitudes of plants attacked, and generally 
the shape of the gall differs in each, and is produced by a different 
insect. Hartig, Westwood, Giraud, and others, have described 
some very unusual forms. The oak trees afford a refuge for, and 
nourish many kinds of gall-flies, which do not spare the trunks, 
the leaves, the twigs, or the roots. Oak-apples, or the rounded 
masses attached to oaks in the summer, some small and others 
large, readily attract the attention; they are galls that have been 
produced by a Cyuips. They might be taken to be the fruit of 
the oak, and they are to the eye miniature apples—oak apples. 
The largest are always at the base of the leaves, and within them 
there is a cavity tenanted by one larva; it remains there in a dull 
and stupid condition during the winter, and is transformed into 
a pupa in the spring. The adult insect is developed within the 
cellule, and is obliged to cut its way out into the world with its 
mandibles. This Cyzzps is of a bright brown colour, and is called 
Cynips quercis baccarum. 
The small oak-apples that usually are found in plenty on the 
lower surface of the leaves are formed by another species—Cyzips 
guercis folit. 
The branches of the oak in the spring-time are often covered 
with nodules, some of which are very large and irregular in 
shape. Their surface is smooth, their colour light green, passing 
into red in some spots, and there are usually several on a twig 
close to each other. They are constructed on a different plan to 
those of the gall-leaf insects, for they contain twelve or fifteen 
cellules, or more, each of which contains a larva. These kinds 
of Cynips fly in the middle of the summer, and there are probably 
two generations in each year. They are called Cynips terminalis, 
on account of the peculiar ornamentation of the female. The 
sexes differ much in their shape and colour; the male has large 
transparent wings, and its body is of a uniform bright fawn colour, 
whilst the female has no wings whatever, and is brownish, the 
end of the abdomen being of a shiny black tint. 
