between lepidopterous larve and ther surroundings. 365 
with grey, 1 smaller and darker with less grey. Two 
smaller larvae, probably in the 4th stage, or perhaps at 
the beginning of the 5th, were respectively lightish and 
darkish-brown. 
June 15th. One of the darkest larvae had become mature 
and was removed. 
June 18th. One of the darkest larvae become mature and 
was removed, 
June 20th. Two very dark larvee mature and removed. 
One very small one dead, Of the 6 in the last stage, 4 
were very black, in 3 cases overspread with dull greyish 
patches; 1 was greyish on the dorsal surface, lighter 
grey elsewhere ; the 6th and smallest somewhat resembled 
that last described. 
June 26th. All had become mature except that last- 
mentioned, which had become a dark brownish-black. 
July 2nd, No further change. 
July 12th. The larva had become mature and was 
removed, 
CONCLUSIONS. 
The power of the black surroundings is evident, the in- 
fluence of the green being only seen in the occasional grey- 
ness on the black larvze,and especially in the one larva which 
was entirely grey. The brownish shade of the larva which 
was the last to reach maturity is unusual on the twigs of 
Turkish oak. These probable effects of the green on the 
larvae which had been longest exposed to the influence of 
black (being the last to pupate), are contrary to the results 
observed in the other experiments. 
Bs, A. betularia. 
June 3rd. Five betwlaria larvee in green surroundings 
up to the end of the 4th stage were transferred to 
black. They were changing the 4th skin and 20°5 mm. 
long. 
June 5th. One larva, a green one, was on a black twig, 
the others on the leaves. Four were brownish-green and 
1 medium brown, All were advancing in the 5th stage 
and about the same size, 
June 20th. Three large in the 6th stage, 1 dark smoky- 
black ; 1 greyish smoky-black, and 1 intermediate, greenish- 
brown. One small one dead, 1 missing, 
