204 PTILOTA. 



defenceless inhabitant inclosed within, and which, when 

 carefully examined, proves to be a truly necromorphous 

 pui)a. 



But there are other insects belonging to the necromor- 

 phous section, Avhich indisputably prove the real identity of 

 these apparent differences, and show the necessity of looking 

 at the subject in the most general manner. Thus some 

 coleopterous pupae (example, the StaphylinidcB), and some 

 hymenopterous pupae (example, the Chalcididce), are as 

 truly mummy-formed as the lepidopterous pupai, whilst 

 other coleopterous pupaj (example, Anthrenus, Attagenus) 

 do not quit the larva skin, and are therefore amorphous. 

 Again, some necromorphous pupae (example, the Trichoptera), 

 although inactive during a great part of their remaining in 

 that state, become as active, previous to assuming the per- 

 fect state, as any of the Isomorpha ; and lastly, if we care- 

 fully examine the obtected pupa of a butterfly, we shall at 

 once perceive that the only character which separates it from 

 the necromorphous, or incomplete pupa of a beetle, is, that 

 its limbs are laid more compactly upon its breast, each, how- 

 ever, being inclosed in its distinct sheath. 



The preceding considerations appear sufficiently to prove 

 that the pupa state of insects is a distinct state, and that in- 

 stead of being regarded merely as the matured state of the 

 larva, it would be more correct to regard it as the immature 

 state of the imago. This will be still more evident from a 

 more precise investigation of the form and structure of pupae. 



1. Of those species which undergo the metamorphosis 

 inchoata of Latreille, the pupae differ only from the pre- 

 ceding state by an increased size, and occasionally an in- 

 crease in the number of segments. Crabs, spiders, Tuli 

 (figs. 27, 28, and 29), centipedes, lice, spring-tailed insects 

 {ThysanurcB), are subject to this kind of metamorphosis, 

 which is so slight that it is impossible to decide whether one 



