the colours of certain Lepidojytei'a. 



313 



May 23. — 5 in green surroundings and 4 in black were now nearly 

 mature, being about 4'2'0 mm. long. There was a very marked difference 

 between the 2 sets of larvm, especially on the ventral sides. They were 

 now (8 a.m., May 23) reversed, the 5 being put in dark and the 4 in green 

 surroundings, to test whether rapid changes of colour could occur ; 2 in 

 black and the 2 solitary larvaj in green remained small, and were inter- 

 changed also. 



May 24. — Noon. No change of colour in the interchanged larvae. All, 

 exceiJt 1 large and 2 small dark larvie and 2 large light ones, were 

 removed for painting. 



May 26. — 10-30 a.m. The smaller of the 2 dark small larviv now 

 seemed to have been affected slightly by the green surroundings, for it 

 was somewhat lighter. The others were unchanged, and were now 

 replaced in their original environments. The 2 now replaced in green 

 were about mature, and very light coloured ; the other 3, one of which 

 was quite mature, being dark. 



The other larvae were subsequently replaced, and the 

 pupae of the two lots kept separate. Many eggs were 

 obtained from moths which emerged from the pupae of 

 dark larvae, and these formed the material from which 

 the experiments were continued in the following year, as 

 described below. 



This experiment showed conclusively that the larvae 

 are very sensitive to the colour of their immediate 

 environment, and also that the effects are gradual, and 

 cannot be rapidly reversed by changing the surroundings. 

 Greater effects might perhaps have been produced if the 

 8 larger larvae had been subjected to experiment at an 

 earlier age. 



1888. 



These larvae were obtained from eggs laid by moths 

 developed from the dark larvae of the previous year. 

 From the arrangement of the eggs it seemed probable 

 that they were the product of a single pair of moths, but 

 it was impossible to feel sure of this. The experiments 

 are shown in tabular form below. 



Experiment I. 

 Dark Surroundings. 



Experiment II. 

 Green Surroundings. 



Experiment III. 



Green Surroundings 



in the dark. 



Larvae hatched and intro- 

 duced April 27, 29, and 

 May 2. 



May 6. — Dark twigs in- 

 troduced ; 17 larvte alive. 



May 18. — Larvse about 

 19-3 mm. long. A very 

 marked difference between 

 these and II. ; seems to have 

 appeared suddenly during 

 the last 24 hours. 



Blay 19.— 17 larvae. 



Larv:i3 hatched April 27, 

 28, and 29, and introduced 

 same dates. 



May 14. — 17 alive ; 8 

 were separated and placed 

 in lots of 3, 3, and 2 in 3 

 small cylinders, subject to 

 the same conditions ; 9 were 

 left in the original cylin- 

 der. 



Larvfe hatched and 

 introduced April 30 

 and May 1 ; 1 added 

 May 4. 



3Iay 14. — 1.5 alive ; 

 many had escaped. 



May 22.— 14 larviu. 



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



