ix] PAST AND PRESENT 113 



company with the larvae of their own species. On 

 the leaves of a willow tree he may observe leaf- 

 beetles (Phyllodecta and Galerucella) together with 

 their grubs, all greedily eating the foliage ; or lady- 

 bird beetles (Coccinella) and their larvae hunting and 

 devouring the ' greenfly.' All of these insects are, 

 however, Coleoptera, and the adult insects of this 

 order are much more disposed to walk and crawl 

 and less disposed to fly than other endopterygote 

 insects. Their heavily armoured bodies and their 

 firm shield-like forewings render them less aerial 

 than other insects; in many genera the power of 

 flight has been altogether lost. It is not surprising, 

 therefore, that many beetles, even when adult, should 

 live as their larvae do; since the acquirement of 

 complete metamorphosis they have become modified 

 towards the larval condition, and an extreme case of 

 such modification is afforded by the wingless grub- 

 like female Glow-worm (Lampyris). 



With most insects, however, the larva must be 

 regarded as the more specially modified, even if 

 degraded, stage. Miall (1895) has pointed out that 

 the insect grub is not a precociously hatched embryo, 

 like the larvae of multitudes of marine animals, but 

 that it exhibits in a modified form the essential 

 characters of the adult. Comparison for example can 

 be readily made between the parts of the caterpillar 

 and the butterfly, whose story was sketched in the first 



c. i. 8 



