ANNULOSA. 543 



2. Many insects, which have wings in the perfect state, 

 are observed to acquire, first, the rudiments of them, and 

 afterwards all their parts, and to assume the form of the 

 perfect insect, while passing through this period of youth, 

 without any particular transformation. In this state they 

 are called Pupce seim-completa. Like the pupae completae, 

 they likewise move and eat like the perfect insect. In the 

 different kinds of pupae which remain to be considered, the 

 animal neither eats nor moves. It derives its nourishment 

 from its stores of fat. 



3. After retiring to some suitable place, the larvae of 

 some insects cast their skin, and disclose the body of an 

 ovate form, enveloped with a coriaceous covering, forming, 

 within, separate sheaths for the different external organs. 

 In this covering all the changes of form and structure take 

 place, which prepare it for maturity. These are termed 

 Pupae, incomplete. 



4. Other insects, likewise, upon changing their skin for 

 the last time in their larvas state, appear within a coriaceous 

 covering, destitute, however, of any sheaths within for the 

 external organs; these last being closely applied to the 

 body. These are termed Pupa obtecta. 



5. In the last form of the pupa, the skin, instead of 

 being cast off, is changed into the coriaceous covering. 

 Such are termed Pupa coarctata. 



All insects which, in the pupa state, do not eat, and are 

 motionless, are careful to retire to situations, sufficiently 

 remote from enemies, and of suitable temperature and mois- 

 ture. In many cases, the larva forms an exterior covering, 

 in which the pupa may be lodged with greater safety. 

 This covering is in some composed of threads of the well 

 known substance termed silk. Sometimes only one or two 

 threads are required to keep the pupa in a proper position ; 

 in others, the silk is woven into cloth, or so matted toge- 



