the colours of certain Lepidoptera. 305 



examined, and 19 were found alive, and were distinctly 

 darker than either of the other lots. This result is ex- 

 ceptional, for larvae brought up in this way are usually 

 lighter than those among an abundance of dark twigs in 

 strong light. 



Other experiments were made to test whether the 

 pupa is susceptible to surrounding colours. I have 

 already described and figured the pupa as dimorphic 

 (Trans. Ent. Soc. Lond., 1885, p. 319, PI. VII., figs. 

 20 and 21), "one form being light bluish green, covered 

 with white dots, and the other dark brownish green, 

 sprinkled with black dots." The brown larva becomes 

 green in its cocoon before pupating {I. c, p. 319, and 

 tig. 19). Many larvae in this condition, and in the 

 earlier brown state, were placed in paper cocoons of 

 various shades, — black, green, white, — but no corre- 

 sponding differences were seen in the pupae. I should be 

 glad for this experiment to be tried again, employing 

 more natural substances, such as brown leaves and bark, 

 green leaves, &c., and. applying these conditions to a 

 somewhat earlier period of larval life. 



There is no doubt that the larvae of this species are 

 highly sensitive to the greens and browns in their im- 

 mediate surroundings, but there is at present no reason 

 for the belief that the pupa is similarly susceptible. 



8. Experiments in 1886 upon Selenia lunaria. 



Moths bred from purchased pupae paired and laid the 

 eggs which provided the material for these experiments. 

 I am not sure whether all were produced from the same 

 parents. The experiments began June 8 — 11, when the 

 larvae were arranged as follows : — 



I. Dark surrouiidivgs. — Fed on Quercus cerris, the 

 dark twigs being present as well as the leaves. About 

 30 were introduced June 9, of which only 19 were alive 

 June 26, and the same number July 13, when they were 

 compared. These larvae were extremely dark as a whole, 

 and very different from those in II., being much darker 

 than the darkest of the latter. 



II. Green surroundings. — Fed on leaves of Quercus 

 cerris without any dark twigs. Introduced June 9, and 

 18 alive July 18. They were very variable, but none 

 very dark, and much lighter than the larvae of I. It 



