88 INTRODUCTION TO 



or of taking food. But although this is the general 

 condition of pupa, it is by no means universally so ; 

 many scarcely differ in appearance from their larvae 

 and are equally capable of moving about, and equally 

 voracious. This affords a convenient means of sepa* 

 rating them into two great divisions, the one compre* 

 hending such as resemble their larvae, the othef 

 those which bear no resemblance to their larvae. To 

 the first of these divisions belong all those pupae which 

 Linnaeus called complete, viz. the Orthoptera, Hem- 

 iptera, (with some exceptions,) and certain tribes 

 among the Neuroptera. The principal perceptible 

 difference between these pupae and the perfect in- 

 sects consists in the wings not being fully deve- 

 loped ; but these organs approach gradually to a 

 state of greater maturity with the age of the pupa, 

 although without breaking through the case chat con- 

 tains them. The general form of the body, and the 

 organization of the mouth, are similar in both states, 

 the other differences besides the one indicated, 

 when such exist, being confined to the legs or certain 

 other parts of structure which are of utility to the 

 pupa when it differs in its economy, as sometimes 

 happens, from the imago. Thus the pupa of Cicada 

 has the forelegs greatly thickened and adapted fot 

 digging, because in that stage of its life it lives be- 

 neath the ground ; after undergoing its final change 

 it frequents trees, and the fossorial legs, being no 

 longer useful, disappear. The respective states 

 of larvae and pupa in the tribes in question being 

 not indicated by any marked character, it is oftet 



