INSECTA. 427 



The wood would appear to be the worm's only subsistence ; and, if 

 so, it is one of the most curious and singular circumstances respecting 

 the food of animals ; for, in most animals, the food far exceeds the size 

 of the animal ; but in this they must be well proportioned. 



[Subkingdom Articulata. 

 Class Insecta.] 



Of Insects. 



A singularity in the external figure of some animals, arising from the 

 mode of union of the three great parts of which animals of a certain 

 degree of perfection are composed, has given rise in the mode of classing 

 to a division called ' insects.' These three parts, in the more perfect 

 animals, are the ' head,' the ' chest,' containing the heart, lungs, &c, 

 and the 'belly,' containing the digestive powers, with the parts of 

 generation. 



Although in the insect these three divisions do not exactly contain 

 the above-mentioned parts, yet they do in some degree. The insect is 

 the first of the imperfect [invertebrate] animals that have most of their 

 particular parts brought together into their respective places ; the head, 

 for example, being distinct for the brain and all the senses. But although 

 the parts appropriated for particular uses are distinct in themselves, 

 yet they are of different shapes, so as not all to come into the same 

 places [as they do] in the more perfect [animals] ; for in this class 

 [Insecta] the heart is continued along the back, and the lungs are 

 dispersed over the whole body : but the belly is allotted to the di- 

 gestive powers, and, in most, to the parts of generation. The union 

 between the head, thorax, and abdomen in this class of animals being 

 very slight, gives the idea of an incision. The part which is analogous 

 to the thorax is only a fixture to the legs and wings with their muscles, 

 not being a containing part : therefore the abdomen becomes the com- 

 mon reservoir ; even the salivary glands are within it. Their cuticle 

 and bone is the same, besides answering many of the other purposes of 

 fife, as claws, pincers, &c. They are the first [animals in the ascending 

 scale] which have the five senses; and the first that are of distinct 

 sexes 1 . They have nothing similar to a pelvis; therefore all their feet 

 come out from the thorax : of these they are obliged to have three pairs, 

 and the last go as far back as the belly to support it, or the weight of 

 the belly would tilt up the head or fore part. 



1 [Many Entozoa and certain plants, e. g. palms, are dioecious.] 



