360 Professor E. B. Poulton on colour-relation 



June 2Qth. The bro^Ynish-greeD larva iu the 5th 

 stage was dead. The 2 large ones as last described. 



July 2nd. The greenish intermediate larva had become 

 mature and was removed. The distinct green one was 

 very large, beiug 64"6 mm. long. The green groimd-colonr 

 was somewhat dull, and the brown dorsal line broad but 

 not dark. The remaining larva was in the 5th stage and 

 intermediate. 



July 12th. The last-mentioned larva was dead. The 

 other had pupated. 



CONCLUSION. 



The effect of a dark environment during the 2nd stage 

 alone, although slight, is very remarkable. The grey 

 which overspread the green forms may be compared to the 

 grey patches on the dark form in this and so many of the 

 other experiments. 



A-. A. hetularia. 



May 29th. The 5 hetularia larvae re-transferred to green 

 surroundings after they had been in black during the 2nd 

 and 3rd stages. 



May ^\st. All 5 larvae were advancing in the 4th stage, 

 and all dark or distinct brown. 



June 2nd. Two larva;^ were changing the 4th skin and 

 22"0 mm. long ; the 3 others advancing in the 4th stage. 

 Appearance unchanged. 



June 5th. One larva changing 5th skin and medium 

 brown : 2 half-grown in 5th stage and 1 nearly at end of 

 it ; 2 dark brown, 1 of the larger pair light brown. The 

 5th larva in 4th stage and dark brown. 



Jitne \4fth. Four approaching the end of the 6th stage ; 

 2 very black and 2 similar, except that the ground-colour 

 was overspread with light grey, in one case slightly, in the 

 other thoroughly. The latter was nevertheless a darkish 

 larva. The 5th larva was changing the 5th skin, and 

 green with a brown median dorsal line. 



June loth. One dark larva had become mature and 

 was removed. 



June 2Qth. One dark larva mature and removed. The 

 remaining 3 larvae were all in the 6th stage. The grey 

 colour of one of the dark larvae was still very distinct. 

 The brown dorsal line was pronounced upon the green 

 larva. 



