VARIATION IN PUP2B. 203 



the ill effect which its employment produces in reference to 

 the natural distribution of insects, we shall at once see that 

 this distribution, ingenious as it is (especially with reference 

 to the septenary classification of insects, maintained by its 

 author), and indeed any distribution of insects from the cha- 

 racter of metamorphosis alone, evinces the absolute neces- 

 sity of recurring to other characters. Thus, whilst one 

 division of the Amorpha comprises the Diptera with true 

 coarctate pupse, the other comprises not only all lepidopterous 

 insects, but also many Diptera, which must surely be more 

 nearly allied by nature to the other Diptera than they are to 

 the Lepidoptera. Moreover, even amongst the adermatous 

 Diptera, many species exhibit a necromorphous rather than 

 an amorphous appearance : when, however, we regard the 

 real character of the coarctate pupa (which corresponds with 

 the Amorpha dermata), we are at once confirmed that the 

 real character of the dipterous pupa is necromorphous and 

 not amorphous. The pupa of the bees is truly necromor- 

 phous : its larva forms, or else is by its parents or their 

 assistants (neuters) inclosed in, a cell, where it is safely 

 guarded, so that it has only to cast off its skin, and appear 

 in its naked, defenceless, but yet defended pupa state. But 

 the flesh-fly is differently situated : its functions in nature are 

 such, that the least waste of time would be to their preju- 

 dice. In its first production this is amply provided against, 

 in an anomalous but most effectual manner, by the eggs being 

 hatched within the body of the parent. During its growth as 

 a larva it undergoes no moultings of the skin, which are 

 attended in other insects with a certain loss of time, and on 

 arriving at its full growth the same character is still retained. 

 The skin is not cast, but, with the most admirable foresight 

 on the part of the Great Contriver of both great and small, 

 becomes an envelope answering all the purposes of a silken 

 cocoon or a waxen cell, and serves for the protection of the 



