VAKIABLE PROTECTIVE RESEMBLANCE IN INSECTS 145 



pressed for food, and are obliged to search for it with 

 extreme care. 



I have also shown that the cocoon of the Green 

 Silver Lines Moth {Halias prasinana) can be modified in 

 colom- Hke that of the Small Eggar.^ This species also 

 passes the winter in the chrysahs state, when the brown 

 colour is highly protective. One of my caterpillars 

 had begun to spin a brown cocoon upon an oak leaf 

 (see fig. 35). I then removed the caterpillar to a white 

 box ; it remained motionless for several hours n nd then 



Fig, 35, — Brown cocoon begun 

 by caterpillar of Green Silver 

 Lines Moth {B.prasinana)\xpon 

 iiH oak leaf ; natural size. 



Fig. 36. — White coooon spun by same 

 caterpillar when transferred from 

 oak leaf to wiiite paper; natural 

 size. 



Fig. 37.— The brown cocoon of 

 Green Silver Lines spun upon 

 an oak leaf. 



spun a white cocoon (see fig. 36). The brown cocoon 

 of the same species is shown in fig. 37. Eemembering 

 the experiments upon the Small Tortoiseshell, it is 

 very probable that the colour of the cocoon was deter- 



Proc. Ent. Soc. Lond. 1887, pp. 1. li. 



