ENTOMOLOGY. 
123 
of a telescope, and can readily be moved in any direc- 
tion. Such a confirmation is well exemplified by the 
Staphylinidee, which elevate and twist about their 
abdomen with the utmost facility, and even turn it 
over the back to push the wings under their short 
cases.* The whole of the segments are lined in- 
ternally with a soft membrane, which connects 
them, and retains them in their places, without im- 
peding their movements. This membrane becomes 
visible when the abdomen is in a distended state, as 
in a gravid female, when the abdomen seems to form 
a bag, with horny plates arranged in a certain order 
over its surface. 
An opening for the respiratory organs, which 
ramify through the body, may be observed near the 
lateral margin of each segment. These openings are 
surrounded with a hard ring, and are called spiracles 
or air-holes, (Stigma, Spiracula.) 
It has been well observed that each of the three 
great divisions of the body is the appointed seat of a 
separate set of organs, all of them alike important in 
the animal economy. As the head contains the 
organs of mastication, and the thorax those of mo- 
tion, so the abdomen is the appropriate site of the 
generative organs. These, however, are chiefly in- 
ternal, and will be most conveniently considered 
when treating of the anatomy of the abdomen. Such 
external appendages, too, as are more or less acces- 
sory to the organs alluded to, as well as various others 
which, as far as known, have no connection with 
See Lacord. Introd. I. 447. 
