378 



INTKODUCTION TO 



enquiry, but can be used very serviceably, in prevention of 

 recurrence of attack. 



Pupa (Chrysalis). — It is much to be regretted that we have 

 no generally-adopted word, excepting " chrysalis " (which is 

 commonly used in the case of Butterflies or Moths), to describe 

 the second stage of insect life in which it is changing from 

 the state of Icn'va to that of the complete insect. 



Whilst in this condition it is for the most part without 

 power of feeding and perfectly inactive, lying (as in the case 

 of Beetles, — the common Cockchafer for instance, — Bees and 

 Wasps, and some others) with the limbs in sheaths folded 

 beneath the breast and body, or (as with Butterflies and 

 Moths) protected by a hardened coating secreted from the 

 pores of the creature within, when it casts its last larval 

 skin. The method of this change may be easily observed in 

 the case of the caterpillar of the Peacock Butterfly, which 

 fastens itself Ijy the tail, and then (after its black and silver- 

 spotted skin has cracked) by infinite wriggling and struggling 

 passes this cast-off skin backward, till it is pressed together 



Larva and pupa of Cockchafer. 



at the tip of the tail ; and the creature from within appears 

 in its new form as a bright green chrysalis, ov i^upa. It is 

 covered with a moist gummy exudation, which quickly 

 hardens and forms a protecting coat, and in due time (if left 

 unharmed) the Butterfly inside would crack through this and 

 appear from within the case ; but if it is wished to observe 

 that the beginning of the change to the Butterfly form has 

 taken place already, one of these chrysalids may be dropped 

 into a little warm turpentine, or turpentine and Canada 

 balsam, directly the caterpillar-skin has been cast ; this will 

 soften the gummy coating just mentioned, and the limbs of 

 the future Butterfly will be seen. 



In some cases the change takes place (as with various but 

 not all kinds of Flies) in the hardened skin of the maggot, 

 which may be called a "Fly-case"; and in some (as with 

 Plant Bugs, Aphides or Green Fly, Grasshoppers, and some 

 others) this state of piqia is an active one, in which they 

 move and feed, and resemble the perfect insect, excepting in 

 having more or less rudimentary wings or wing-cases. 



