m.l METAMORPHOSES OF INSECTS. 41 



CHAPTER III. 

 ON THE NATURE OF METAMORPHOSES. 



IN the preceding chapters we have considered the 

 life history of insects after they have quitted the 

 egg ; but it is obvious that to treat the subject in 

 a satisfactory manner we must take the develop- 

 ment as a whole, from the commencement of the 

 changes in the egg, up to the maturity of the animal, 

 and not suffer ourselves to be confused by the fact 

 that insects leave the egg in very different stages 

 of embryonal development. For though all young 

 insects when they quit the egg are termed " larvae," 

 whatever their form may be (the case of the so-called 

 Pupipara not constituting a true exception), still it 

 must be remembered that some of these larvae are 

 much more advanced than others. It is evident that 

 the larva of a fly, as regards its stage of develop- 

 ment, corresponds in reality neither with that of a 

 moth nor with that of a grasshopper. The maggots 

 of flies, in which the appendages of the head are rudi- 

 mentary, belong to a lower grade than the grubs of 

 bees, &c., which have antennae, mandibles, maxilla;, 



