CH. XVIII.] PARASITICAL INSECTS, ETC. 255 



interior of old galls is filled with particles of fibre 

 reduced to a kind of black powder, which is all that 

 separates these worms from each other, and which 

 does not prevent their meeting. These larvae not 

 only differ in colour from the ordinary ones of the 

 oak, and many other trees, but they also differ in the 

 form of their parts. They are terminated anteriorly 

 by a little point, the apex of which is brown ; if this 

 part be investigated from beneath with a powerful 

 lens, no vestige is discovered of those two brown 

 teeth common to the other worms of a multitude of 

 galls, each of which is situated at an equal height 

 upon each side of the head, and which close together, 

 but in lieu we perceive a small brown mark. Upon 

 closely examining this brown mark, and touching it 

 with any pointed instrument, it is found to be of a 

 consistence as hard as horn ; and we then distinguish 

 that the end of it nearest the head is not only larger 

 than the other, but that it consists of two straight 

 parts, almost parallel to each other, but which do not 

 touch. The simplest and most distant from its apex 

 passes out of an aperture which is apparently the 

 mouth, into which the fragments ground by the fur- 

 cate portion, or the juice extracted from them, enter ; 

 we can, however, but guess upon this subject, for we 

 cannot hope to observe such delicate parts in action, 

 particularly in an insect which is so ill at ease when 

 exposed to the light." Reaumur detected in the 

 galls much smaller worms, which were almost white, 

 but coloured red or yellow within. These larvae are 

 supposed to be parasites on the true gallfly. The 

 latter is considered a two-winged insect, while the 

 former is conjectured to have four. 



We will now mention one which attacks the 

 flowers of the chamaedrys, and while the majority 

 of them are in full bloom. Reaumur observed some 

 which were considerably larger and more swollen 

 than the others were when they opened, and which 

 were, nevertheless, closed. Each of the latter sup- 



