the colours of certain Lepidoptera. 435 



Of two pupae in compartments of the middle row, 

 one was fixed on the junction of black and gold, the head 

 being on the latter, while the other was fixed below the 

 junction, so that the posterior balf of the body was 

 against black, and the anterior half against gold. The 

 first pupa was dark, with very little gold, the second 

 light, and with the gold spots rather developed (the large 

 triangular spot was dull, the anterior part of each dorsal 

 spot somewhat golden). Here, while there is no evidence 

 for local effects, a lighter pupa was formed when a rela- 

 tively larger surface was exposed to gold than when the 

 surface so exposed was smaller. 



Another pupa was fixed to the glass in a compartment 

 of the upper row, with the middle of the body opposite a 

 gold band, the head and posterior part equally opposite 

 black. The pupa was dark, with very little gold. 



Two were fixed to the glass of compartments of the same 

 row, with the middle of the body opposite black, the head 

 and posterior end equally opposite gold. One was a 

 light variety with little gold, the other intermediate 

 between a dark and light variety. 



A single larva was introduced earlier in the summer 

 into one of the shallow black cells, covered in front 

 with white opal glass, described in the Experiments on 

 V. io (see p. 423). The pupa was attached to the glass, 

 and was moderately golden, being rather on the light 

 side of an intermediate variety. This result, with the 

 others recorded above, seems to show that the species 

 has a greater susceptibility to white and gilt surround- 

 ings when conflicting with black than is the case with 

 V. io. The difference between the effects produced 

 by the two opposite backgrounds when used separately 

 is, however, so much less in F. atalanta as to render 

 the species far less suitable for the purposes of tliis 

 enquiry. 



There was not the least evidence for any local influence 

 upon the pupae, so that the results of these experiments 

 confirm the previous conclusions as to the physiology of 

 the process. 



