II. A. 



Black paper 

 leaves, &c. 



Up to Aug. 18 same 

 surroundings as II. ; 

 then brown bircli 

 twigs introduced with 

 food, and also pieces 

 of black paper rough- 

 ly cut into the form 

 of leaves ; also black 

 floor and roof. 



Aufj. 18. — The 6 

 larvae which had 

 been removed at this 

 date from II. were 

 now placed in dark 

 surroundings. 



III. 



Darkness. 



IV. 



Green leaves. 



Orange paper leaves. 



Sept. 15. — 5 larvae 

 in last stage, 3 being 

 dark brown and 1 

 greenish brown ; 1 

 small and reddish 

 brown ; 1 pupa. 



For about a fort- 

 night, eiiiling Aug. 18, 

 enclosed in a darkened 

 cylinder (covered with 

 one thickness of black 

 tissue paper). Dark 

 twigs of birch not ex- 

 cluded. 



Aiiq. 18. — Compared. 



A. .' 



B. Dark reddish 



brown . . . i 



C 



D. Eeddish brown 2 

 Light greenish 



brown . . . 1 



Placed at this date 

 in a larger cylinder 

 covered with 2 thick- 

 nesses of black paper 

 and black floor. 



Sejyt. 15. — Only one 

 larva left ; greenish 

 brown. 



The effect of dark Insufficient to draw 

 surroundings added conclusions, but so far 

 Aug. 18 is clear when , as it goes, the evidence 

 these larva3 are com- , corresponds with later 

 pared with those of j experiments in show- 

 II. ing that darkness is 



not so effective as dark 

 surroundings in a 

 strong light. 



Kept for last fort- 

 night on birch leaves 

 and green twigs under 

 a shade of one thick- 

 ness of faded yellowish 

 green tissue paper. 



Aug. 17. — Examined 

 and compared. 



A. Dark reddish 



brown ... 1 



B. Dark reddish 



brown . . . 1 

 Green . . . . 1 

 Greenish brown . 3 



C. Reddish brown . 3 

 Light greenish 



brown ... 1 



D. Reddish brown 3 

 Light reddish 



brown ... 2 



15 



Put in a larger cy- 

 linder ; tissue paper 

 changed. 



Sept. 15. — 1 pupa ; 1 

 nearly mature green 

 larva, with brown along 

 back. Others escaped. 



Kept for about a fort- 

 night on birch leaves 

 and twigs (brown ones 

 included), intermixed 

 with pieces of orange 

 paper cut roughly into 

 the form of leaves. 



Auij. 18. — Examined 

 and comj^ared. 



A 



i; 



C. Greenish brown 3 

 Tending in diffe- 

 rent degrees to- 

 wards reddish 

 brown, two being 

 the typical colour 6 



D. Reddish brown 1 



E. Reddish brown, 



varying ... 4 

 Light greenish 



brown ... 1 



15 



Sept. 15.— Only 2 re- 

 maining ; both dis- 

 tinctly green, with a 

 brown line down back. 



Insufficient evidence, 

 but corresponds with 

 II. in showing suscep- 

 tibility to green sur- 

 roundings. 



Results correspond 

 with those obtained in 

 1892, showing the 

 power of orange sur- 

 roundings in producing 

 green larvte. 



TRANS. ENT. SOC. LOND. 1892. — PART IV. (DEC.) 



2c 



