between lepidopterous larve and their surrowndings. 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 larve 
which first became mature were certainly influenced by the 
green environment of the three last stages, inasmuch as 
the final appearance was a dark smoky-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 larva 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 larvee grew more slowly after May 25th, and 
thus passed a relatively longer time in the green 
environment. 
Cl. A. betularia. 
June 3rd. Two betularia larvee at the beginning of the 
5th stage re-transferred to green surroundings after they 
had been in black for the 3rd and 4th stages, 
June 5th. 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. 
June Tth. A fourth larva changing its 4th skin and a 
fifth at the beginning of the 5th stage were similarly 
re-transferred, 
June 14th. Three larvee 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 large in the 6th stage, smoky-black 
overspread with grey. The black ground-colour resembles 
that of the larvee still in black surroundings. 
June 23rd. Two had become mature and were removed. 
June 26th. Two mature and removed. The 5th was 
TRANS. ENT. SOC. LOND, 1903.—PART lI. (ocT.) 25 
