14 BRITISH INSECTS 



from the flowers ; the bee's grub is exempt from all 

 self-effort by the instinctive provision made by its 

 parent, or by adult members of its community. In 

 view of facts such as these, and because every animal 

 is seen to fit accurately the particular niche which it 

 occupies in the scheme of existence, it is scarcely sur- 

 prising that the larvae of many insects differ widely 

 from their adult forms ; nor can we wonder that an 

 intervening period of quiescence (the pupa stage) has 

 become necessary to bridge over the gap which exists 

 between the two totally distinct phases of life. To 

 quote the late Lord Avebury, the necessary trans- 

 formation, in the case of a caterpillar, " could hardly 

 take place while the insect was growing fast, and 

 consequently feeding voraciously ; nor, if the change 

 could be thus effected, would the mouth, in its inter- 

 mediate stages, be in any way fitted for biting and 

 chewing leaves. The same reasoning applies also to 

 the digestive organs. Hence the caterpillar under- 

 goes little, if any, change, except in size, and the 

 metamorphosis is concentrated, so to say, into the 

 last two moults. The changes then become so rapid 

 and extensive that the intermediate period is neces- 

 sarily one of quiescence." 



Before concluding this chapter, a few words must 

 be said respecting classification. Formerly its chief 

 aim was to arrange things in convenient groups 

 according to their obvious agreements and differences. 

 But nowadays the schemes of classification put for- 

 ward by naturalists are deliberate attempts to express 

 relationship not mere outward similarity, be it noted, 

 but actual kinship. For since the days of Charles 

 Darwin naturalists have become firmly convinced 

 that all existing plants and animals have descended 



