hetiueen leindopterons larvx and their surroundings. 367 



brown markings the other 2 can only be considered as 

 rather on the green side of intermediate. 



July 12th. The smallest larva was still feeding and still 

 intermediate. The other two had become mature and 

 were removed. There was no further change. 



CONCLUSIONS. 



These results are deeply interesting. The 6 larvae 

 which first became mature were certainly influenced by the 

 green environment of the three last stages, inasmuch as 

 the final appearance was a dark smokj^-black with a pair 

 of distinct grey patches on each segment, instead of the 

 well-known intense dead black which is the characteristic 

 effect of the black-barked twigs of Turkish oak. At the 

 same time, the remarkable susceptibility to this stimulus is 

 seen in the pronounced darkness of these 6 larva3 after only 

 a single stage (of 5 days' duration) had been passed among 

 black twigs. It is interesting to note that the 3 inter- 

 mediate larvse grew more slowly after May 25th, and 

 thus passed a relatively longer time in the green 

 environment, 



C^ A. betularia. 



June Srd. Two hetularia larva? at the beginning of the 

 5th stage re-transferred to green surroundings after tiiey 

 had been in black for the 3rd and 4th stagfes. 



June 6tJi. A third larva, changing its 4th skin, was 

 similarly re-transferred. It was of a light brown colour. 

 Of the 2 former, 1 was nearly at the end of the 5th stage 

 and dark brown, the other rather smaller and darkish 

 brown overspread with grey. 



Jicne 7th. A fourth larva changing its 4th skin and a 

 fifth at the beginning of the 5th stage were similarly 

 re-transferred, 



June lifh. Three larva? in 6th stage, smoky-black with 

 prominent light grey markings especially distinct in one 

 of them. One in 5th stage and 1 changing 5th skin, both 

 dark chocolate-brown with a little grey. 



June 20th. Four larg3 in the 6th stage, smoky-black 

 overspread with grey. The black ground-colour resembles 

 that of the larvse still in black surroundings. 



June 2ord. Two had become mature and were removed. 



June 2Qth. Two mature and removed. The 5tli was 



TRANS. ENT. SOC, LOND. 1903. — PART III. (OCT.) 25 



