POOD OF INSECTS. 39? 



their food of a construction altogether different =*. But 

 it is impossible here to attempt even a sketch of the 

 variations in these organs which take place in the apte- 

 rous genera, and in many of the dipterous larvae. Suf- 

 fice it to say that they all manifest the most consummate 

 skill in their adaptation to the purposes of the insects 

 which are provided with them, and which can often 

 employ them not only as instruments for preparing food, 

 but as weapons of offence and defence, as tools in the 

 building of their nests, and even as feet. 



Some insects in their perfect state, though furnished 

 with organs of feeding, make no use of them, and con- 

 sume no food wliatever. Of this description are the 

 moth which proceeds from the silk-worm, and several 

 others of the same order ; the different species X)f QE- 

 strus, and the Ephemerae, insects whose history is so 

 well known as to afford a moral or a simile to those 

 most ignorant of natural history. All these live so 

 short a time in the perfect state as to need no food. — 

 Indeed it may be laid down as a general rule, that al- 

 most all insects in this state eat much less than in that 

 of larvae. The voracious caterpillar when transformed 

 into a butterfly needs only a small quantity of honey ; 

 and the gluttonous maggot, when become a fly, con- 

 tents itself with a drop or two of any sweet liquid. 



While in the state of larvae the quantity of food con- 

 sumed by insects is vastly greater in proportion to their 

 bulk than that required by larger animals. Many ca- 

 terpillars eat daily twice their weight of leaves, which 

 is as if an ox, weighing sixty stone, were to devour 

 every twenty- four hours three quarters of a ton of grass 

 * Plate VIL Fig. 8. 10. 



