238 INSECTA. 



pupx or nymphs^ and in the \\i\v(i perfect insects. It is only 

 in the last state that they are capable of reproduction. 



All Insects do not pass through these three states. Those 

 which are apterous issue from the ovum with the form they 

 are always to preserve(l): they are said to be without a 

 metamorphosis. Of those that have wings, many experience- 

 no other change than that of receiving them : these are said 

 to undergo a demi-metatnorphosis . Their larva resembles 

 the perfect insect, with the single exception of the wings, 

 which are totally wanting. The nymph only differs from the 

 larva in possessing stumps or rudiments of wings, which are 

 developed at its final change of tegument, and render the ani- 

 mal perfect. Such are the Cymeces, Grylli, &c. Finally, 

 the remaining Insects provided with wings that are said to 

 undergo a complete metamorphosis ^ are at first larvse, resem- 

 bling caterpillars or Worms, and then become motionless 

 nymphs, but presenting in that state all the parts of the per- 

 fect insect contracted, and as if wrapped in a bandage. 



In the nymph of the Coleoptera, Neuroptera, Hymenop- 

 tera, &c., these parts, though closely approximated and in 

 contact with the body, are free ; but they are not so in that of 

 the Lepidoptera and of many Diptera. An elastic or solid 

 skin is moulded over the body and its external parts, forming 

 a kind of case for it. 



That of the chrysalides of the Lepidoptera merely consist- 

 ing of a simple pellicle applied to the external organs, follow- 

 ing their contour in every direction, and forming, for each of 

 them, so many moulds, like the envelope of a mummy, allows 

 us to recognize and distinguish them(2) ; but those of Flies 

 and Syrphi, formed of the dried skin of the larva, resem- 

 ble an egg -like shell. It is a species of capsule or case in 

 which the animal is shut up(3). 



Many larvae, before they pass into their pupa state, pre- 



(1) The Pulex, the female Mutillw, the Working Ants, and some few other In- 

 sects excepted. 



(2) Pupa obtecta, L. 



(3) Fupa coarduta, L. 



