216 
Dr. Kidd on the 
N 
substance than the upper, and are covered entirely with a 
coarse down, which probably gives the animal a more firm 
hold while in the act of burrowing. In the last segment is 
situated the vent, formed by three oval flaps, two below, and 
one above. This segment sends out from each side of its 
upper surface two caudal antennae, as I have ventured to call 
themj of a tapering form, which differ essentially in struc- 
ture from those of the head, inasmuch as they are not jointed 
in. any part of their extent, excepting at their very com- 
mencement : they are furnished with short hairs set compa- 
ratively closely about every part ; among which are inter- 
spersed long single hairs. These caudal antennae are evidently 
very sensible, and serve probably to give the animal notice 
of the approach of any [annoyance from behind ; they are 
partially hollow throughout great part of their extent, and 
muscles may be traced into them from the inner and adjoin- 
ing part of the abdomen. 
The legs. The anterior legs passing out from under the 
hind part of the thorax, advance by the side of the head in a 
direction parallel to each other, which is their natural posi- 
tion while the animal is at rest. I should deem it a servile 
adherence to system were I to describe the parts composing 
these legs by the terms strictly indicative of the order of 
their succession ; for, thus, that part which answers so emi- 
nently to the character of a hand, must be called the tibia. I 
shall beg leave therefore to state principally that the fore- 
leg of this insect consists of three main parts, with a lateral 
appendage attached to the last of them. The two first of 
the three parts bear some general resemblance to the claw of 
the crab ; being short and thick, for the purpose of affording 
