INSECTS IN GENERAL. 51 



vivid imagination cannot conceive the means by which per- 

 ception is produced. We imperfectly puzzle out, how the 

 grosser parts of organs are disposed inter-relatively, but this 

 is all we can do ; for matter, however arranged or modified, 

 cannot produce intellect, cannot of itself create that per- 

 ception, which the organ excites ; or even should we adopt the 

 absurd creed of the materialists, and admit that matter may 

 be so organised as of itself to perceive and think, do we in 

 the slightest degree diminish the difficulty before us, or gain 

 one atom of knowledge on the subject ? 



There are, moreover, on the head of insects divers regions, 

 whose development, colours, depressions, and other peculiari- 

 ties have given characteristic distinctions to the naturalist. 

 It will be sufficient here to name them. The occiput, which 

 is articulated with the corslet, sometimes by a single condyle, 

 sometimes by two, is sometimes truncated, rounded, flatted, 

 depressed, prolonged into a sort of neck, &c. The vertex or 

 summit of the head ; the front (fro7is), the cheeks {gencB), 

 between the eyes and mouth ; the chin {mentum), on which 

 the under lip is articulated, &c. 



The corslet, or thorax, is that part of the trunk situated 

 between the head and the abdomen. It has been quite suffi- 

 ciently described in the text for all general purposes. From 

 the description there, it is easy to judge that the form and 

 extent of its various parts, must differ greatly in the diffe- 

 rent orders. Thus, the mesothorax is but little developed in 

 the coleoptera and orthoptera, which have certain elytra of 

 but little usage in flight. In the cigalae, the epimeros is pro- 

 longed under the first ring of the abdomen, to form the great 

 concave plate which covers the instrument of song in these 

 insects. The four regions of the back are more sensible in 

 the lepidoptera, hymenoptera, and diptera. The episternum 

 is most developed in the libellulse, in the coleoptera, or the 

 metathorax. 



E 2 



