BEETLES 



not add to this little mass. The moulted skins are not 

 entirely thrown off, but each one is added to the preced- 

 ing until a long string is formed, just as in Aspidomorpha 

 miliaris, but at pupation the skins are not thrown off, 

 but still carried, turned over the back of the pupa. 



Laccoptera sp. ? [Note 16, p. 315], makes egg-cases 

 rather like those of Prioptera 8-punctata, and, as in that 

 species and Metriona trivittata, there is only one egg in 

 each case. 1 The larva forms a solid shield of excremen- 

 titious matter, which is turned over the body and the cast 

 skins are worked into the mass. The pupa does not dis- 

 card this mass, as does Prioptera S-punctata, but retains it 

 just as it was left by the larva. 



Hence in these four genera we get the following 

 variation in habit : 



Aspidomorpha : Larva retains chain of moults with 

 particles of loosely attached excrement. Pupa does not 

 retain the chain of moults. 



Metriona : Larva retains chain of moults with a 

 " cross-bar " of excrement on the last (viz. the earliest 

 moult). Pupa retains the chain of moults. 



Prioptera : Larva forms a shield of excrement with 

 moults embedded in it. Pupa does not retain the shield. 



Laccoptera sp. ? : Larva forms a shield of excrement as 

 in Prioptera. Pupa retains the shield. 



It may now be asked what is the value to the species 

 of the peculiar habits of egg-laying and covering the 

 body with excrement. It has been suggested that the 

 formation of egg-cases protects the delicate eggs from 

 drying up and also from the attacks of parasitic enemies. 

 This may well be so, for the eggs are laid in exposed 



1 Laccoptera chinensis lays more than one egg in the case. 

 Kershaw and Muir, Trans. Ent. Soc., 1907, p. 250. 



