456 Mr. Poulton's/«?'f/icr experiments upon 



Light Sueroundings. 



Experiment IV. 



White paper floor & 

 roof, with lumps of 

 chalk scattered on 

 former. 



Cylinder as in I. 



Larvffi of "first lot," 

 except two. 



May 17. — 1 darkest 

 of the large larva and 

 4 of the darkest small 

 ones introduced. 



May 24, morning. — 

 A careful comparison 

 of the I., II., IV. & V. 

 was made, all the larvte 

 being placed on white 

 paper, with the light 

 falling on the same 

 side of them from the 

 same direction. There 

 were no decided effects 

 to be recognised, but 

 perhaps those upon the 

 chalk had become 

 somewhat greyer, and 

 those in dark surround- 

 ings a little browner. 



2 escaped, and were 

 replaced next day by 

 2 dark varieties of the 

 "second lot." Fed 

 from this date on 

 rock-rose alone. 



Jii7ie 22. — 1 had spun 

 cocoon under chalk 

 lump, 1 dead. 



June 27. — Larva in 

 cocoon had pupated. 



July 7. — 1 dead, 1 

 spun slight cocoon. 



July 15. — 2 pupse & 

 1 larva in cocoon. 



Aug. 3. — 1 moth 

 emerged. 



Sept. 4. — Another 

 moth had emerged. 



Experiment V. 

 Arranged as in IV. 



Larvas of "first lot, 

 except one. 



3Iay 17. — 1 inter- 

 mediate large and 4 

 intermediate small in- 

 troduced. 



May 24. — 1 escaped, 

 but another was added 

 the following day — a 

 dark larva from the 

 "second lot." 



July 7. — 1 larva in 

 a cocoon had just pu- 

 pated; 3 died about 

 this time. 



Aug, 14. — 1 moth 

 emei'ged. 



Sept. 1. — Another 

 moth had emerged. 



Experiment VI. 



Arranged as in IV. 



Offered rock-rose 

 alone until June 23, 

 after which nothing 

 was eaten. 



Larvffi of " second lot." 



May 25. — 7 out of 

 the 10 darkest larvae 

 introduced. 



Ju)ie 13. — Ihad spun 

 a slight cocoon under 

 a lump of chalk. 



July 15.— 1 had pu- 

 pated without cocoon. 



Aug. 27. — 4 pupae ; 

 the 3 other larvas had 

 died. 



Sept. 4. — 1 moth 

 emerged. The other 

 pupae died. 



