318 Mr. Poulton's /m*i/ier experiments upon- 



Experiment I. 

 Dark Surroundings. 



Experiment II. 

 Green Surroundings. 



June 26. — 9 larvae introduced ; 

 dark twigs mixed with the food- 

 plant (hawthorn), black paper floor 

 and roof to cylinder. 



June 27. — 13 more larvae added. 



July 14. — Only 4 now alive ; 

 small and brown. 



July 24. — All but 1 much darker 

 than other lot ; that 1 about the 

 same as the 3 in the green cylinder. 



Aug. 12. — 3 alive ; 1 so dark as 

 to be almost black ; another larger 

 one was dark brown, mottled with 

 grey ; 3rd small and dark brown. 



Aug. 13. — The largest larva was 

 painted (see Plate XIV., fig. 3). 



Aug. 28. — The very dark larva 

 continued almost black. There was 

 no trace of green in any of the three. 



Sept. 5. — The largest had spun 

 U15 a few days before. 



Sept. 17.— The less dark of the 2 

 remaining larviu was painted (see 

 Plate XIV., fig. 4), but both were 

 now very dark, and no trace of green 

 was seen on the darker one, except 

 on using a lens. A little green was 

 present on that which was drawn. 



Sept. 28. — The 2nd larva painted 

 had spun up. 



Oct. 4. — The darkest larva had 

 just spun up. It had previously been 

 painted (see Plate XIV., fig. 5). 



June 25. — 29 larvie introduced ; 

 leaves only, with green paper floor 

 and roof to cylinder. 



July 14. — Only 5 now alive ; quite 

 small, and various shades of brown. 

 July 24. — Only three now alive. 



Aug. 12. — Not so large as in I. ; 

 the largest was light brown mottled 

 with grey, and with green apparently 

 showing through in many places ; 

 the next in size was a little darker 

 brown, with a distinct squarish green 

 patch on each side of the humps on 

 the 3rd abdominal. There was also 

 green in other parts, especially on 

 sides of 6th, 7th and 8th abdominals. 

 The 3rd and smallest was darkish 

 brown. 



Aug. 13. — A most striking change 

 had taken place in the last 24 hours 

 in the clearing up of the opaque 

 brown pigment, and the consequent 

 appearance of the underlying green. 

 The whole efl'ect was now as much 

 green as brown. This chiefly applied 

 to the 2 larger larvie ; on the 12th 

 they had been brown mottled with 

 green (as the smallest was now) ; 

 on the 13th they were as much green 

 as brown. 



Aug. 28. — The smaller larva re- 

 mained the same ; the others were 

 not quite so green as on the 13th, 

 but still a distinct greenish brown, 

 a bluish grey "bloom" having ap- 

 peared on the larger one. 



Sept. 17.— The largest, with the 

 "bloom" on it, nearly full-fed, was 

 painted (see Plate XIV., fig. 6) ; 

 the next in size was much lighter in 

 colour, and a yellowish brown with 

 green appearing through in various 

 parts. The smallest was a dark 

 brownish green, but still much of 

 the latter colour present on it. 



Sept. ^3. — One of the larger ones 

 had siDun up a day or two. The 

 lighter large one was painted about 

 this time (see Plate XIV., fig. 7). 



Sept. 20. — The smallest had died ; 

 it was lighter than any in I., but 

 not light like the two larger in this 

 experiment. 



