386 
GALL INSECT. 
egg in each little hole, to the number of seven or 
eight on the same leaf. At the same time she 
injects into each cavity a peculiar and corroding 
liquor, which so interrupts the circulation of the 
sap, that the part near the wound is discoloured, 
and a gradual enlargement takes place. This con- 
tinues to increase, and towards the end of the 
month the excrescence is as large as a marrowfat- 
pea; after which it increases rapidly in size, and 
by the beginning of October has attained its full 
growth ; its surface at this time is dried by the ex- 
ternal air, arid it has assumed the roundness of a 
kernel. This little ball gradually receives its nou- 
rishment, and vegetates like the other parts of the 
tree. 
Under this strong roof, and within the substance 
of the ball, is hatched the little worm ; which on 
slitting open its apartment is found snugly em- 
bedded in the centre, and somewhat resembling the 
small maggot occasionally found in the hazel-nut. 
The interior and pulpy part of the nut affords the 
creature a sustenance accommodated to its nature. 
It eats and digests it, till its transformation first 
into a chrysalis, and then to a fly ; after which it 
gnaws its way through the walls of its prison, and 
immediately launches into the air. 
Upon examining those gall-nuts that were pro- 
duced in the beginning of summer, a small opening 
will be immediately perceived through which the 
fly escaped ; but it must be observed that when the 
right owner quits the habitation it does not cease 
