68 THE BUTTERFLY VIVARIUM. 



the others females. But it is somewhat extra- 

 ordinary that in the cases where the male and 

 female insect, in their perfect state, are of strikingly 

 different forms— the female, for instance, heing a 

 creeping creature, perfectly apterous or wingless, 

 and with a heavy, cumbrous body, while the male 

 is light in form, and provided with broad and richly- 

 tinted wings — even in such cases, no appreciable 

 difference is discernible in the larva state. 



It may be stated here that several attempts have 

 been made to class Caterpillars in a more detailed 

 and closely defined manner than that suggested by 

 the three classes just named. Mr. Maclcay, for 

 instance, in his " Horse Entomological," has sought 

 to create homogeneous groups and families founded 

 on the resemblance of certain larva? to the forms 

 exhibited by other classes of animal life, terming 

 those " chilognatiform," for instance, which more or 

 less resemble the Centipede family. This system 

 has been partly followed by Messrs. Kirby and 

 Spence in their valuable " Introduction to Ento- 

 mology," but it seems to me that, except as far as 

 a convenient set of terms is concerned, such a 

 system of classification will be useless ; as the main 

 classification of insects must always be that founded 

 on their perfect forms, and not on peculiarities 



