INTRODUCTION 



porarily transparent ; the effect is short-lived, as the benzine 

 evaporates rapidly, and the cilia (if long) are liable to be 

 damaged by this method. 



Pupa. 



The pupa is wholly encased in a chitinous integument, 

 rendering the ordinary organs of locomotion useless ; but some 

 pupae, which are subterranean or inhabit the hollow stems of 

 plants, are capable of working themselves along by means of 

 rings of spines on the margins of the abdominal segments. 

 In the more ancestral forms of the Lepidoptera the chitinous 

 envelopes of the antennae, legs, and other organs are more or 

 less free and detached from the general integument, though 

 incapable of movement; whilst in the more advanced forms 

 the cases of these organs are fused with the general integu- 

 ment. The only recorded instance of active organs in a 

 Lepidopterous pupa is that of Micropteryx, in which the large 

 mandibles and labial palpi are functionally active. The seg- 

 ments of the abdomen may be either free (movable at their 

 base) or fixed, the number of free segments differing in different 

 groups and genera ; in the earliest forms the segments are all 

 free, but the number of free segments tends continually to 

 diminish ; in certain Papilionina and Tineina all are fixed. 



Usually the pupa is enclosed in some sort of cocoon, but 

 this protection is sometimes dispensed with. In most cases it 

 is concealed beneath the surface of the ground or amongst 

 leaves and refuse ; in the case of mining species it is often 

 within the mine ; less frequently it is entirely exposed, attached 

 by the tail and sometimes by a median silken girdle, and is then 

 usually protectively coloured. 



When dehiscence (the breaking-up of the pupal integument 

 to allow of the escape of the imago) takes place, in the earlier 

 forms the cases of the various organs remain intact, the organs 

 being simply withdrawn from them; whilst in the more advanced 

 forms the inner wall of these cases, being extremely slight, is 

 practically destroyed, and the general integument is broken up 

 irregularly. 



Larva. 



In the larva the thirteen segments are usually clearly de- 

 fined ; they are referred to hereinafter by their numbers, 1-13, 1 

 being the head. This is furnished with simple eyes and strongly- 

 developed mandibles ; antennae are usually rudimentary, but 



