170 



METAMORPHOSIS 



striking of the differences between Insects with perfect and thos 

 with imperfect metamorphosis, yet there is reason for supposing 

 that the pupa and the pupal period are really of less importance^ 

 than they at first sight appear to be. In Fig. 85 we showec 

 how great is the difference in appearance between the pupa an( 

 the imago. The condition that precedes the appearance of the 

 pupa is, however, really the period of the most important changeJ 

 In Fig. 8 9 we represent the larva and pupa of a bee ; it will 

 seen that the difference between the two forms is very great, 

 while the further change that will be required to complete 

 the perfect Insect is but slight. When the last skin of the 



Fig. 89. Larva and pupa 



of 



bee, Xylocopa violacea : A, larva ; 

 upa, dorsal aspect. (After Lucas. ) 



aspect ; C, pupa, dorsal aspect 



C 



B, pupa, ventral 



larva of a bee or of a beetle is thrown off, it is, in fact, the 

 imago that is revealed ; the form thus displayed, though colour- 

 less and soft, is tliat of the perfect Insect ; what remains to be 

 done is a little shrinking of some parts and expansion of others, 

 the development of the colour, the hardening of certain parts. 

 The colour appears quite gradually and in a regular course, 

 the eyes being usually the first parts to darken. After the 

 coloration is more or less perfected according to the species 

 a delicate pellicle is shed or rubbed off, and the bee or beetle 

 assumes its final form, though usually it does not become active 

 till after a farther period of repose. 



11 



