64 THE ENTOMOLOGIST. 



should be attended by tliose of circulation, and that both 

 should be enclosed by those of support throughout their 

 circuitous and manifold ramifications. In Endosteates the 

 bones form a connected system adapted to the especial 

 function of support, and the organs of respiration consist of 

 a single and simple windpipe opening at its upper extremity 

 into the throat, and terminating at its lower extremity in 

 the lungs, where the air which it has received at the throat 

 comes in contact with the blood, and receives the necessary 

 oxygenation to ensure its life-supporting properties. In 

 hexapods we may suppose the same process of oxygenation 

 necessary, but it does not take place at any fixed point, as 

 the lungs : the process goes on in every part of the trunk, in 

 the legs, wings, and antennae, because the windpipe is infi- 

 nitely divided, and accompanies the blood-vessel in all its 

 windings, however intricate, however ramified ; so that the 

 blood is always lubricating and moistening the windpi])e, 

 and thus maintaining it in that condition so essential to the 

 due performance of its functions. 



In both Endosteates and Exosteates the windpipe is com- 

 posed of a series of rings closely appressed together; they are 

 sufficiently strong to maintain their form and position against 

 any pressure that may come from without, but still suffi- 

 ciently flexible to offer no impediment to the free motion of 

 the equally flexible bones, which they invariably traverse 

 from end to end. We have lately heard a good deal of 

 flexible glass : these tubular bones, through which the 

 blood and air constantly circulate, may be compared to 

 flexible glass. They also resemble glass in being frequently 

 transparent, so that the functions, in course of progress 

 within, may be observed and watched from without. This 

 transparency, however, is confined to a few families, and, in 

 these families, exclusively to the wing-bones; the existence 

 of transparent bone in the trunk has not been noticed, and 

 probably does not exist. Moreover, the wing-bones of 

 Coleoptera are almost invariably opaque, and of a dark 

 brown colour, which effectually precludes all examination 

 of the interior. 



This differentiation of the two great provinces of animals 

 — I say ttco, because I make no attempt to cope with the 

 other two, Anosteate and Actiniate — is so totally, so diame- 



