iW2 PTILOTA: IMAGO EXTERNAL ANATOMY. 



The clypeus (c) of Fabricius, or the nose of Kirby and 

 Spence, or the epistomis of Latreille, is an important part 

 of the head, as occasionally, from its developement, and the 

 consequent want of developement of the true upper lip 

 (labrum), it takes the functions of the latter, and serves, as 

 the name imports, and as it was at first employed by Liniwus 

 in the lamellicorn beetles, as a shield for the mouth. That 

 there are grounds for not strictly regarding it in every in- 

 sect as a mouth-shield, cannot be denied; but it would be 

 equally incorrect to reject it on that account, as it would be 

 to reject that of labrum, or upper lip, because the latter 

 organ occasionally is quite unserviceable as a lip. Still less 

 do I feel inclined to regard it as a nose. Its form is very 

 variable, according to the form of the head. Thus, in an 

 elongated head, it will be distinct and square, or rounded ; 

 and in those with a shorter head it is transverse. In the 

 rose beetle it has a deep frontal notch ; in the sacred beetle 

 it is ornamented with several scalloped notches; in the 

 hornet it is subquadrate ; in the grasshopper rounded ; and 

 in the rove beetle transverse. 



The organs of sense affixed to the head are : 



fixed (a), The composite eyes. 



(6), The ocelli, or single eyes. 

 Moveable (c), The antennae. 



(rf), The trophi, or organs of the mouth. 



In relation to the mutual dependence of these organs 

 upon each other, and the general character of the insect, 

 the following admirable passage, by Mr. Newman, extracted 

 from the Entomological Magazine, may be advantageously 

 quoted : " Professor Rang has prettily observed, that every 

 instrument, whether it be for the generation or transfer- 

 ence of power, has a best size and a best form. Nature, 

 in the formation of her instruments, has always adopted 



