INTRODUCTION. XXUl 



from which nerves pass to the eyes, the antennae, 

 and the mouth. 



The situation of the organs of smell and hearing 

 has not been determined ; that they possess this 

 sense is a matter of inference from the various 

 facts offered in the study of their habits. 



The most remarkable circumstance in the history 

 of insects is their metamorphosis. The changes 

 which they undergo fixed the attention of the 

 earliest observers : they exist in four progressive 

 forms : 1. The egg ; 2. Larva, grub, worm, or 

 caterpillar ; 3. Chrysalis, aurelia, nymph, or pupa ; 

 4. Imago, or perfect state. 



The eggs vary in colour, shape, consistence, 

 and the covering with which many are clothed. 

 Some insects deposite them in places where the 

 natural food of the tribe is most abundant ; and 

 without ever having seen their parent, the instincts 

 of the young teach them to act as they had been 

 acted by ; others protect the egg till the larva is 

 produced. In the flesh-fly the first stage of the 

 metamorphosis passes within the body of the 

 parent, and the larva, or worm, is brought forth 

 alive. In some insects the parent retains the young 

 within the body, some time after it has been evolved 

 from the egg, and then gives birth to the pupa. 

 Other insects produce their young in a perfect 

 state, so as to require no farther changes. 



In the larva state the insect appears to attain its 

 greatest weight. In this it moults, or changes its 

 skins several times, and the same colours are not 



