OF INSECTS. 105 



tribe where some species of them are entirely deprived of the sense of 

 smelling, viz. the porpoise, although others of the same tribe [viz. the 

 whalebone whale] have [that sense]. 



Of the Nourishment of Insects. 



The nourishment of this class of animals, problably like that of all 

 others, is, first the common food, secondly the store or reservoir of 

 nourishment laid up while food was plentiful, and thirdly, part of the 

 animal itself, as the wasting of muscles, &c. 



The common food varies in different classes of insects. The store 

 consists of a substance, like fat in sojne, but not of an oily nature ; 

 while in others there is a fat which is oily, as in the humble-bee. The 

 wasting of parts [in its relation as a source of food, by absorption], is 

 probably the same in all animals. 



Of the Store or Fat. 



All winged insects, as far as I know, have a store of nourishment 

 laid up as gleanings out of the common food after having become blood. 

 In the maggot or caterpillar it is hardly oil. This is somewhat similar 

 to this store in most young animals ; but in the full-grown it is a fine 

 oil, in very small cells, like marrow in quadrupeds. This, like the 

 fat in most other animals, is situated in every cavity or interstice of the 

 body, and is most in quantity according to circumstances. It is most 

 in quantity when the caterpillar is going into the chrysalis state : and, 

 in those that five through the winter, as the common fly, female 

 humble-bee, wasp, hornet, &c, it is largest in quantity in the autumn. 



In the chrysalis state many parts are formed out of it, such as the 

 extremities, parts of generation, &c. In those that go into a state of 

 torpidity, the fat is wholly gone by the time the fine weather comes in. 

 We need only kill a fly at each season to be sensible of the truth of 

 this. 



Of the Food of Insects. 



The food of the caterpillar and maggot often differs very much from 

 that of the fly-state in the same insect. Perhaps there are few insects 

 which eat the same food when in the perfect or third state, that they 

 did in the first. However, I believe the wasp and hornet are exceptions, 

 for they seem to feed their young with what they eat themselves. 



The food of insects, when in the maggot or caterpillar-state, is com- 

 monly very juicy, and they themselves are full of moisture. However, 

 this is not always the case with the insect when in the second state ; 



