186t.3 



176 



Second broods ? — August 29th I took, in a wood noar Polegate, specimens of 

 Melitcea Athalia and Sesia cynipiformis 9 . Is it not very late for both these 

 species ? — Id. 



Observations on the occurrence of Colias Hyale in Britain. — The occurrence of 

 Colias Hyale in such unusual numbers and localities this year seems naturally to 

 suggest the idea of a migration of this species, which, however, does not seem to 

 be confirmed by the accounts of its appearance in different localities. 



For instance, on page 107 of the present volume of the Magazine, a corres- 

 pondent states that he took Hyale in fine condition at Margate on or before July 

 27th, and that in a few days afterwards it was common, and by August 7th so worn 

 out as to be hardly worth catching. 



At Haslemere, thirty miles inland, and at a considerable elevation above the 

 level of the sea, the first specimens were met with on August 5th, beautifully fine ; 

 and others from day to day until August 15th, all in good condition. After this 

 date the weather became rough, and they disappeared. 



On August 31st Mrs. Hutchinson tells me a specimen was taken by her son at 

 Leominster, which, when first seen, was perfectly fine, and was only injured a 

 little in catching. 



Now, if this had been a migration of Hyale, and it had become worn so early 

 as August 7th on the south-east coast, it could not well have appeared in fine con- 

 dition at Haslemere from August 5th to 15th, much less at Leominster on August 

 3 1st. Neither, for the same reason, could the specimens taken inland be stragglers 

 from its usual breeding places on the coast. 



On the oth-er hand, it is absurd to suppose that eggs or pupa© could have laid 

 for years waiting for an exceptionably hot sumtaer to bring them to perfection, even 

 supposing that the clover fields, in which they appear to feed, were permanent, 

 instead of being sown in rotation with other crops. 



The only way, therefore, in which I can explain its appearance in such unusual 

 and widely separated localities, is by supposing that when engaged in egg-laying, 

 the female must forsake the ordinary habit of the species, of flying up and down 

 one or two clover or lucerne fields for hours and, indeed, days together, and fly, as 

 it can, very rapidly across the country, laying a few eggs here and there in the 

 various clover fields over which it passes, and that the larvae, in a favourable, i. e, 

 hot and dry summer, feed up rapidly, escaping their worst enemy in this climate — 

 mould, and so the perfect insects are found, earlier or later according to the climate, 

 one, two, or three in a clover field in the inland districts, and in large numbers in 

 those coast districts in which the insect usually occurs. 



Thus I am compelled, contrary to my will and usual practice, to offer a theory 

 in explanation of this unusual visitation, and can only hope that it will be found, 

 ultimately, to be borne out by facts ; but I can give one fact slightly to the point. 



A young friend of mine, Master Stuart Nicholson, of Liphook, near Haslemere, 

 showed me a female which he had taken there on the railway embankment, and 

 said that he disturbed it from a small hollow, and that its wings were not sufficiently 

 hardened to enable it to fly far, so that it flew heavily very short distances and was 

 soon caught ; and the appearance of the specimen, its exquisitely perfect condition, 

 and the brilliancy of its reddish fringes, are strong confirmation of his statement. 

 It certainly never could have flown far. 



