former come from adipose masses in course of formation; the second
from the nourishing fluid or from the blood which laves those
masses.

Including the head, I count thirteen segments. In the middle of
the body these segments are well marked, being separated by a
slight groove; but in the forepart they are difficult to count.
The head is small and is soft, like the rest of the body, with no
sign of any mouth parts even under the close scrutiny of the lens.
It is a white globule, the size of a tiny pin's head and continued
at the back by a pad a little larger, from which it is separated
by a scarcely appreciable crease. The whole is a sort of nipple
swelling slightly on the upper surface; and its double structure
is so difficult to perceive that at first we take it for the
animal's head alone, though it includes both the head and the
prothorax, or first segment of the thorax.

The mesothorax, or middle segment of the thorax, which is two or
three times larger in diameter, is flattened in front and
separated from the nipple formed by the prothorax and the head by
a deep, narrow, curved fissure. On its front surface are two pale
red stigmata, or respiratory orifices, placed pretty close
together. The metathorax, or last segment of the thorax, is a
little larger still in diameter and protrudes. These abrupt
increases in circumference result in a marked hump, sloping
sharply towards the front. The nipple of which the head forms
part is set at the bottom of this hump.

After the metathorax, the shape becomes regular and cylindrical,
while decreasing slightly in girth in the last two or three