ENTOMOLOGY. 
121 
some instances the liind legs are most developed, and 
are far most employed in furthering the insect’s 
economy. This may be witnessed in the pill-rolling 
beetles, ( Ateucki .) 
We have now briefly considered two of the princi- 
pal sections of the body, the head and thorax, and it 
only remains for us to bestow a similar notice on the 
third, namely, the Abdomen. This portion is at once 
known by the absence of all external articulated ap- 
pendages 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 in- 
stances 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 trans- 
verse 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. 
