LEPIDOPTERA. 



The principal nourishment of most caterpilhirs consists of the 

 leaves of vegetiibles : others devour flowers, roots, seeds, buds, and 

 even perforate and subsist on the solid wood of trees ; many are 

 exceedingly destructive to our domestic articles, and destroy skins 

 and woollen stuffs, while some feed on leather, grease, lard, &c., 

 and spare not even our honied stores : several live on one substance 

 alone, while many attack various plants and substances, and even 

 devour each other; but as a recompense for the destructive pro- 

 perties of some, others are kindly provided by the fostering hand 

 of Providence with qualities whose produce gives employment to 

 millions of human beings, — and some are kept within due bounds 

 by the hosts of Ichneumonidae and Chalcididae. 



Caterpillars usually change their skin four times previously to 

 passing to their pupa or chrysalis state ; and they are in general 

 furnished with an apparatus for spinning silk, with which they 

 either line the cells wherein they undergo their changes, or suspend 

 themselves preparatory to that event : these cells are variously con- 

 structed in the different groups, and as I proceed I shall notice their 

 diversified structure under their respective genera. 



In the generic distribution of the contents of this truly elegant 

 order of insects, I may confidently assert that I have hitherto 

 laboured without other assistance than that derived from the still- 

 incomplete work of the lamented Ochsenheimer, no one in this 

 country, till recently, having devoted their attention to this depart- 

 ment of the science beyond the mere capture and investigation of 

 the species and their varieties. I consequently fear that my limited 

 knowledge of exotic forms may occasionally betray me into the 

 venial error of proposing genera upon characters, which may be so 

 moderated by intervening extra-indigenous forms, as to be deemed 

 of no importance when compared with their congeners; — but tiiose 

 individuals, who maintain that genera are unimportant, and lead to 

 no practical use, when new species with coiuiecting characters are 

 discovered, might with equal propriety deny the presence of salt 

 in the ocean, because the sources of rivers are fresh, and the jietual 

 point where the saline impregnation commences cannot be ascer- 

 tained, owing to the very gradual manner in which it is incorporated 

 with the water. I do not, however, here intend to advocate the 

 expediency of adding- to the vast numbers of modern genera, which 

 it aj)j)ears necessary to adopt; though, wore I disposed to vindicate 

 the propriety of forming them, or of adding to those of Linne, — 



