402 Mr. F. Merrifield and Mr. E. B. Poulton on 



producing the darkest pupae is very clearly seen. The 

 iDlack paper did not act quite as strongly through the 

 thickness of glass (4, 5, 6) as when the pupje were in 

 direct contact with it. When tlie pupa; were upon the 

 glass window at a varying distance from the black ]iaper, 

 the effects were much less marked (7). Black in shade (4) 

 produced an intermediate pupa, but the parts of the roof of 

 case(6) which werefarthest removed from the light produced 

 pupae which were rather darhcr than those nearer to it. 



Dark sticJcs (8) produced as great an effect as blick, but 

 little or no influence was exerted at a distance (9). 



Dirty white 2^f<int (10) gave rise to a great variety of 

 pupae, all forms being represented among the thirty-one 

 forms tabulated, the dark and intermediate degrees (1) and 

 (2) strongly predominating. 



Clear glass (11) produced intermediate and liglit pupae, 

 while in Da.rkness (12) they were strongly green — six out of 

 seven being (3 h). This result is so remarkable and 

 extreme an effect of darkness that further experiments are 

 to be desired. It is probably to be explained by the 

 strong normal tendency of this species to produce go^een 

 forms in the absence of any effective stimulus (see 9, 14, 

 24, in support of this : the pupae on the glass removed 

 I'rom the stimulus are greener than those subjected to it). 



Dead reeds (IS) produced intio'mediate and liglit pupae; 

 at a distance (14) light and green ones wei'e formed. 



Dull green reeds (15) produceil chiefly light pupae (3 a) 

 with some intermediate (2) and a single green one (3 h) ; 

 on the glass they were all ligld (16). 



Oat-straiv (17) caused the pupae to become light (3 a) and 

 green (3 h), while at a distance they were light (18). 



Dutch "gold" (19, 20, 21) tended strongly towards light 

 pupae (3 a), the only exception being in the case of a green 

 pupa (3 h) formed when the gilt surface was the other 

 side of glass (20). At a distance (21) the single pupa was 

 similar to those fixed on the gilt. 



Green paper (22, 23, 24) produced almost exclusively 

 light pupae (3 o), the action through glass (23) being similar 

 to that of the coloured surface itself. At a distance a 

 single green pupa (3 b) was formed. 



Green cabbage-leaves (25, 26) on the other hand produced 

 far more green than light pupee, affording a most interesting 

 comparison with the artificial colour. On this point see 

 the Appendix in which the constitution of the light 



