62 STATES OF INSECTS. 



cially since the change of organs will come more regu- 

 larly under our notice upon a future occasion. 



Winged insects, many branchiopod Crustacea, and the 

 Batracian reptiles, have been observed by Dr. Virey to 

 bear some analogy to the mammalia, aves, &c. in another 

 respect. In leaving their egg, they only quit their first 

 integument, answering to the chorion or external envelope 

 of the human foetus ; they therefore still continue a kind 

 of foetus, so to speak, more or less enveloped under other 

 tunics, and principally in their amnios, or the covering 

 in which the foetus floats in the liquor amnii*. This the 

 butterfly does in the pupa case ; and its birth from this, 

 under this view, will be the true birth of the animal. In 

 the human subject, the ova upon impregnation are said 

 to pass from the ovary through the Fallopian tube into 

 the uterus. In the insect world, upon impregnation, the 

 eggs pass first from the ovaries into the oviduct, answer- 

 ing to the Fallopian tube, which in them terminates in 

 the ovipositor, or the instrument by which the parent 

 animal conveys the eggs to their proper station : there 

 is, therefore, nothing properly analogous to the uterus in 

 the insect, and the substance upon which the larva feeds 

 upon exclusion answers the purpose of a placenta. 



After this general view of the most modern theories 

 with regard to the metamorphosis of insects, I shall in the 

 present and some following letters, treat separately of the 

 different states through which these little beings suc- 

 cessively pass. 



The first of these is the Egg state, the whole class of 

 insects being strictly oviparous. Some few tribes indeed 



a A r . Diet, d'Hist. Nat. xx. 352, 



