Larva of the Hymenoptera. 127 
Spence, Latreille, &c. for not having noticed as much. It is 
evident,” he adds, “ that these writers considered the tw-o first 
segments as the head, and justly, for although as yet destitute of 
the usual organs, they were in fact the head only requiring further 
development.” 
I would however observe, upon Mr. Shuckard’s statement that 
the larvae of the males of the aculeate Hymenoptera will necessarily 
have an additional segment, that there would be ample grounds 
for its adoption, if the abdomen of the male bee consisted of ten 
segments and that of the female of nine; but when we find that 
the loss of certain segments has actually taken place in both sexes, 
we cannot by any analogy trace a necessary equal loss in the 
individuals of opposite sexes. It would be as correct to assert, 
that the larvae of the female insects, mentioned by Mr. Mac Leay, 
necessarily possessed more segments in the larva state than the 
males. In all the apod larvae w'hich I have examined, I have 
constantly found the same number of segments, viz. fourteen.* 
Moreover, it is w T ell known that sexual peculiarities (and the 
loss of abdominal segments is one of the most striking) are not 
developed in the larva state. And lastly, in the larva of the 
Ichneumon, which I have already noticed, there are, as usual, 
fourteen segments, although it is evident that the insect is a 
female by the possession of the ovipositor, of which the rudiments 
are distinctly visible through the skin of the larva. 
I will merely add, that Swammerdam evidently considered the 
first segment alone as the head, the first pair of spiracles being 
represented as placed upon the third segment of the body ; and 
that the justice of considering the two anterior segments of the 
larva as forming together the head of the pupa, rests only upon 
the authority of Dr. Ratzeburg, having by all previous authors 
been regarded as representing not only the head, but also the first 
or prothoracic segment of the perfect insect. 
* Since this paper was read, I have reared both sexes of a species of Crabro, 
from larvm precisely agreeing in this number of the segments. 
