BEETLES 179 



are gregarious, feeding and resting in serried masses 

 on their food-plant. When a larva moults, the skin 

 is not thrown right off the body, but remains attached 

 behind- and that next moulted is attached to the previous 

 one, and so on, till a full-grown larva is furnished with 

 a long chain of old skins, borne erect on a process at 

 the hind-end of the body. The larva also has the habit 

 of fastening particles of excrement to the spines of the 

 last moulted skin, but they are very loosely attached 

 and soon fall off. It is a habit which, as we shall see, 

 has descended from a far more elaborate one. When 

 the larva is ready to turn into a pupa, it fastens itself 

 to a leaf and then partially throws off the last larval skin 

 a part, however, still remaining attached to the pupa- 

 while the chain of old skins is thrown off entirely. The 

 pupae are found in little groups and are conspicuous 

 objects. 



The female of Prioptera octopunctata does not form 

 an egg-case, but deposits her eggs singly on the under 

 sides of leaves. She first lays down a thin membrane, 

 or layer of viscous secretion which hardens to a 

 membrane, and on this is laid an egg, which is again 

 covered with another membrane, the egg being thus 

 enclosed in a flat semi-transparent case. But this is 

 not all, for over this case is placed a sort of roof to 

 which particles of excrement are attached ; this accom- 

 plished, at another point on the same leaf, or even 

 on another leaf, the process is repeated again and again 

 until all the eggs are laid. 



The larva is a conspicuous white-spotted creature, and 

 it has the habit of covering the spines at the end of 

 its body with excrement, forming a solid shield with 

 an irregular sort of fringe along the hind-border. The 



