Severin and Severin—Anatomical Studies of Cimbex. 39 
The males were usually found basking in the hot sunshine up¬ 
on the leaves of these willows. The female; were often taken 
while working their saws under the epidermis of the lower 
surface of the leaves, where they deposited their eggs on one 
or both sides of the mid-rib. Sometimes, however, the females 
were found girdling the branches with their strong mandibles. 
Methods. 
For general dissection, the specimens were prepared by in¬ 
jecting 95 per cent alcohol into them with a hypodermic 
syringe. For histological purposes, the dorsal integument 
was removed and they were then thrown into the preserving 
fluid. Several methods of fixation were used, viz., Flemming’s 
weak and strong solutions, Perenyi’s fluid and a saturated 
aqueous solution of corrosive sublimate. In the last-named 
method, the insects were either killed in hot water, to which, 
after a few seconds, an equal amount of a saturated aqueous 
solution of sublimate was added, or the insects, after being 
killed in hot water, were thrown directly into a hot saturated 
solution of sublimate. Here the insects were allowed to re¬ 
main from twenty to forty minutes. They were then thor¬ 
oughly washed in running water, and finally preserved by plac¬ 
ing them in 50, 70 and 95 per cent alcohol consecutively. 
After this, the different parts of the internal organs were dis¬ 
sected out and carried through absolute alcohol and xylol, in¬ 
filtrated with 52° paraffin and finally sectioned, the sections 
being from 4 to 12/* in thickness. The stains, Flemming’s 
safranin, gentian violet and orange G\ and haematoxylin fol¬ 
lowed by eosin, gave most excellent results. 
Anatomical Structure of the Digestive Canal. 
The pharynx (Fig. 3, ph ), which lies wholly within the 
head, is dorsiventrally flattened, being a little broader and 
more compressed at the anterior than at the posterior end. 
Dorsally, the pharynx has a thick layer of circular muscles; 
ventrally, there is a brown chitinous plate, which ends poste¬ 
riorly in two prolongations (Fig. 1, pi). The pharynx, in pass- 
