180 A NATURALIST IN BORNEO 



larval skins, as they are moulted, become involved in 

 this mass, and are more or less completely hidden in it. 

 The excrement is laid on to the spines in a very peculiar 

 manner : the anus is evaginated for a considerable 

 distance and plasters the excrement smoothly over the 

 surface. This shield is generally carried turned forwards 

 over the back, but the larva can flick it backwards and 

 forwards when irritated. Just before pupation the larva 

 casts the excrementitious shield, and then fastens itself 

 securely to a leaf of its food-plant. The pupa is a broad 

 and somewhat flattened object, with curious spinose hooks 

 projecting from the first, second, and third abdominal 

 segments. Portions of the last larval moult are retained 

 at the end of the body, but otherwise the pupa is freely 

 exposed. Another species, Metriona trivittata, forms an 

 egg-case described as follows by Mr. W. Schultze * : 



" It is laid on the upper or under side of the leaf and 

 always contains a single egg. The egg itself is inclosed 

 within a very thin primary case and the latter is placed 

 under a remarkably perfect, roof-like cover fastened to 

 the leaf. This cover is thin and has two nearly parallel, 

 longitudinal carinae, which are somewhat excurved at one 

 end, but run together at the other end where they are 

 bent and erect. The area between the carinae has a 

 semicircular impression, but the area outside of this is 

 sloping. . . . Numerous regular, fine striae are visible. 

 The egg of this species is always free from any excre- 

 mental covering. The color of the egg-case is a very 

 pale green." 



The young larva attaches particles of excrement to a 

 pair of long spines at the end of the body, forming a 

 sort of cross-bar between them, but subsequently it does 

 1 Philippine Journ. of Science, (Ser. A.), III. (1908), p. 267. 



