BEETLES 171 



is nothing inherently impossible in the view that the 

 same limited metamorphosis may occur in members 

 of a third family; in fact, we may go further, and say 

 that the female larvae, and female adults of the Malayan 

 Lycoid species, are in all probability indistinguishable 

 in their external anatomy. But can it be possible for 

 the male larva also to undergo no metamorphosis ? I 

 think it quite probable, for the following reason. In all 

 winged insects the future wings and wing-covers of 

 the adult are formed in the body of the larva ; they 

 are developed as thickenings and folds of that layer 

 of the body-wall known as the hypodermis, and in 

 this stage of development are known as imaginal rudi- 

 ments. As the larva grows in size they grow too, 

 and when the larva casts its last skin and becomes a 

 pupa, the imaginal rudiments of the wings and wing- 

 covers unfold and are visible as wing-pads. The legs, 

 antennae, eyes, and other adult organs are all developed 

 from imaginal rudiments inside the body of the larva, 

 so that we can truly say that a larva is not a distinct 

 organism, which towards the end of its life suddenly 

 changes into a pupa, the pupa eventually suddenly 

 changing into an adult, but that a larva is a stage 

 of gradual growth, containing within its body all 

 the organs of the adult : it is merely an adult in 

 embryo. 



The adult female of the English Glow-Worm, Lampyris 

 noctiluca, is larviform, that is, though in many respects 

 different from the larva, yet it resembles it in the 

 soft grub-like body and in the entire absence of wings 

 and wing-covers. If we examine the larva of the 

 female beetle we shall find that there are in it no 

 imaginal rudiments of wings and wing - covers, but 



