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Rh some instances the hind legs are most developed, and are far most employed in furthering the insect's economy. This may be witnessed in the pill-rolling beetles, (Ateuchi.) We have now briefly considered two of the principal sections of the body, the head and thorax, and it only remains for us to bestow a similar notice on the third, namely, the. This portion is at once known by the absence of all external articulated appendages similar to those of the anterior segments, and a greater simplicity of composition, consisting merely of several consecutive horny segments or rings, in all cases closely joined, and in some instances overlapping each other. The greatest amount of these segments is nine; for the entire number in an insect never exceeds thirteen, and of these one is formed by the head, and three are occupied by the thorax. It often happens, however, that the number seems much less, in consequence of several being united, or so overlapping each other that they cannot be observed. In general the dorsal segments seem more numerous than the ventral; although the reverse of this obtains in some instances. A difference in this respect is not unfrequently a sexual distinction. The shape is too various to admit of a determinate definition in a few words, but a transverse section very generally makes an approach to a rectangular triangle, the base being uppermost. The mode of attachment to the thorax is nearly the same in all cases, although there is an apparent difference depending on the shape of the basal portion. When the latter is broad, as in conical shaped abdomens,