126 
Mr. J. O. Westwood on the Apod 
follow that the terminal segment of the imago must be in like man- 
ner pushed entirely out of the body of the larva; but this is not the 
case, because in the imago some of the abdominal segments of 
the larva have disappeared under the reduced form of organs of 
generation. 
I should certainly have hesitated in offering these observations 
in opposition to the views of Dr. Ratzeburg, were we not enabled 
thereby to trace out, most satisfactorily, the analogous cases 
offered in the development of other groups of insects, and had 
I not, by direct observation, ascertained their insufficiency. 
Several years ago, I carefully watched the progress of transfor- 
mation in the apod larvae of numerous Ichneumonidce, and noticed 
that previous to assuming the pupa state, they had changed con- 
siderably in form; several of the anterior segments assuming a 
harder appearance, behind which the body was constricted; the 
eyes of the future pupa, moreover, appeared through the skin of 
the hinder part of the second segment. They generally remained 
thirty-six hours under this form, previous to casting off the skin 
of the larva. On examining some of these, however, which I 
placed in spirits, I find that the tips of the antennae of the pupa 
extend into the first segment of the larva ; that the head of the pupa 
occupies a portion of the second segment of the larva ; that the first, 
narrow, leg-bearing segment or prothorax of the pupa occupies the 
remainder of the second and part of the third segment ; that the 
second thoracic segment or mesothorax occupies the remainder of 
the third and a small portion of the fourth segment; and that the 
third thoracic segment or metathorax of the pupa occupies the 
fourth segment of the larva, which is in fact its true analogue. 
Our indefatigable member Mr. Shuckard has started an inge- 
nious theory relative to the subject of the present observations, 
referring to Dr. Ratzeburg’s figure of the larva of Apis meliifica, 
which is represented with fourteen segments. He observes, in a 
note appended to the 35th page of his Translation of Dr. Bur- 
meister’s valuable Manual, “ Whether this arose from his having 
figured the larva of the male of that insect, I do not know, for 
the text does not elucidate it; but the accompanying figure 
appears to be the pupa of the male, as it has seven segments to 
the abdomen. I am not aware that it has been before observed, 
that the larvae of the males of the aculeate Hymenoptera will 
necessarily have an additional segment. Ratzeburg seems to take 
great merit to himself for having discovered that the larva of the 
Hymenoptera are headless, as he says, and seems to insinuate 
a censure upon Swammerdam, Reaumur, De Geer, Kirby and 
