between lepidopterows larve and their surroundings. 315 
of Gastropacha quercifolia by Mr. W. Holland, on July 
22nd, 1898, enabled me to experiment on this interesting 
species, which is well known to present grey and lichen- 
hike forms. The company, evidently the product of a 
single batch of eggs, was so numerous that I was able to 
start four experiments with fifteen larvae in each, on 
July 28th. All were fed on hawthorn, the food-plant on 
which the larvze had been found. This in three cases was 
intermixed with environments more or less harmonizing 
with known varieties of the larva—the rough black-barked 
twigs of the Turkish oak, bramble-stems of a rich reddish- 
brown colour, and sticks bearmg an abundant growth of 
lichen (probably Ramalina farinacea in all cases). In the 
fourth case the larvee were as far as possible restricted to 
the green leaves and youngest shoots of their food-plant. 
It was, however, impossible altogether to exclude shoots 
of greyish and reddish-brown shades, and these probably 
produced some effect. 
At first the young larve rested chiefly on the food- 
plant, but soon preferred the bark of the older wood. The 
change took place simultaneously in each of the three 
sets containing dark bark and lichen, as will be seen by 
a glance at the following summary of Mr. Holland’s careful 
notes :— 
| | 
is I. UI. 
Hinton: Food- Black Food- | Hehen’ | Pood- | Reddish- 
plant. bark. plant. oe c ¢ plant. brown bark. 
bark. 
Aug. 1. 12 3 14 1 14 1 
Aug. 5. 4 I 3 i hr ie uaa 
Aug. 9. 3 12 1 14 hy AS 
* 3 on muslin roof, + 1 missing. 
There is no reason to suppose that these effects were 
due to any gradual recovery from disturbance. The re- 
cently hatched larvae were found at the tip of a young 
shoot on July 22nd, and it is probable that by August 5th 
the period had been reached when they begin to seek the 
older wood for the diurnal rest. After August 9th only 
single larvee were found except upon the environments 
which had been provided, and it is probable that, under 
