60 MECHANICAL FUNCTIONS. 



speaks of the peril of this moment in the following lan- 

 guage : " When the observer perceives how much the 

 prow of the little bark sinks, and how near its sides are 

 to the water, he forgets for the moment, that the gnat is 

 an insect, which, at any other time, he would destroy ; 

 nay, he becomes anxious for its fate, and the more so if 

 the slightest breeze plays on the surface of the water ; 

 the least agitation of the air being sufficient to w r aft the 

 creature with swiftness from place to place, and to make 

 it spin round and round. Its body folded in its wings, 

 bears a greater proportion to the little skiff, than the 

 largest mass of sail to a ship ; it is impossible not to 

 dread lest the insect should be wrecked ; once laid on 

 its side on the water, there is no escape. Generally, 

 however, all terminates favorably, and the danger is over 

 in a minute." 



STRUCTURE OF INSECTS. 



163. Having detailed the steps by \vhich nature pro- 

 duces a perfect insect from the egg, and shown also how 

 these natural processes vary in several different orders and 

 species, it is now proper to say something of the struc- 

 ture of these beings, in order to show by what means they 

 perform the functions of life. 



164. Insects, as we have seen, and as common observa- 

 tion evinces, vary exceedingly in their forms, habits, and 

 dispositions, and they must consequently vary in respect 

 to their structure, since each species must be furnished 

 with organs and instruments by which it is precisely 

 adapted to the situation and condition in w r hich it is 

 placed. But although there is so much variety in their 

 appearance, all insects consist of only three principal 

 parts, viz, the head, trunk, and abdomen. 



165. In order to illustrate this subject, we will take one 

 of the beetle-tribe, and divide it into sections, and by means 

 of plans show the names and uses of the several parts. 

 The insect here represented, is the carabus sycophanta } 



What are the principal sections of an insect ? 



