306 Mr. Vouiton's further experimeiits. 



should be remarked that the leaves of this species of oak 

 are very dark green. 



III. Green surroundings. — Fed on leaves alone of elm, 

 and from July 3 on variegated elm, the leaves of which 

 are of course much lighter. Introduced June 8, and 

 5 alive July 13. These were much lighter than II., 

 and 3 out of the 5 extremely light. These larvae were 

 advanced in size. 



IV. Green surroimdinfis. — Fed on leaves alone of 

 QuercAis cerris, in a cylinder surrounded by a single 

 thickness of green tissue-paper, and a roof of the same. 

 20 larvae were introduced June 10 and 11, but most had 

 died by June 26, and, on July 13, only 3 small darkish 

 larvae were left. The paper screen had prevented the 

 leaves from being seen, so that they had become brown 

 and withered, accounting for the failure of this experi- 

 ment. 



There is no doubt that these larvae are highly sensitive. 



9. EXPEKIMENTS IN 1887 UPON THE LARV^ AND PUP/E 



OF Ephyra OMICRONARIA. 



(See Table, page 307.) 



In addition to the experiments of which details are 

 given on the opposite page, there were others which are 

 not noted. Dark surroundings were employed chiefly in 

 the form of intermixture with dead brown leaves, princi- 

 pally of ivy and oak. There was also another set of 11 

 larvae reared successfully in almost complete darkness 

 (surrounded by one thickness of black tissue-paper). The 

 larvae in nearly all cases became pupae, many dozens beiug 

 produced, and giving rise to images ; but, as with the above 

 experiments, the results were invariably negative. Every 

 larva and every pupa was green, and this although large 

 numbers of the latter were fixed to brown leaves, on 

 which they were conspicuous, and although most of the 

 former had been surrounded by these dark objects for 

 nearly the whole of their lives ; for the leaves on which 

 the stock of larvae was kept often became brown, and dark 

 twigs of the food-plant were invariably present during 

 the early stages, if not always (as was the case with 

 most larvae). There is no doubt that E. oniicronaria is 

 not sensitive to the surrounding colours. 



It must, however, be remembered that the species only 

 exhibits a trace of the dimorphism which is so marked in 

 the allied E. ijendularia and E. punctaria. Nevertheless 



