Adjustment of colour in various pup^, etc. 387 



part to the wood (somewhat darkened by age), and in 

 part to the perforated zinc of two ordinary rectangular 

 breeding-cages. It is clear that the two latter sets of 

 pupae had been formed from captured larvse, while the set 

 attached to reeds may have been, in part at least, found 

 so attached in the open. Mr, Peel is not sure upon the 

 point ; but the fact that reeds, and reeds only, have been 

 selected is in favour of this interpretation. The majority 

 of the pupae have now emerged successfully, and nearly all 

 of those that remain are still healthy. Very few have 

 died. The entire absence of parasites in this set of larvae, 

 as compared with their excessive abundance in Mr, 

 Merrifield's continental individuals is of high interest, and 

 suofsests the same conclusion as that at which I arrived 

 last year in breeding large numbers of Continental and 

 English larvae of Vanessa urticse, viz. that the greater 

 abundance of birds in this country may, by destroying 

 parasites, compensate for their direct attacks on the 

 species of Lepidoptera (see Report of British Association, 

 1898, Section D). I will now give the results of the 

 examination which was made on May 3rd, 1899. 



14 pupx attached to reeds. 



Thirteen pupae were distinct light yellow-green (1 a). 

 Of these 2 were fixed at some distance from each other 

 on the same reed, while 10 were on separate reeds. Just 

 below the thirteenth pupa was fixed the single exception 

 a dark grey pupa (2 h). 



1 9 pupse upon ivood or zinc. 



In the breeding-cage v^^hich contained the reeds, one 

 dark grey (2 ?>) pupa was lying loose upon the floor, and 

 another of the same kind (2 li) was attached to the zinc. 



In another breeding-cage 5 pupae were attached to the 

 zinc, in a curved line, near together. From above down- 

 wards their arrangement was — 



2 pupae intermediate between dark and light grey 



(2 a, h). 

 1 pupa dark grey (2 h). 

 1 „ again intermediate (2 a, h). 

 1 „ light grey (2a). 

 Thus the central pupa was darkest, as though some 

 influence had been exerted by the neighbouring larvae or 

 pupae (as is so markedly the case in Vanessa). 



