220 [March, 



Admitting, however, tliat drainage and "high farming " may pos- 

 sibly be the cause of the extinction of the species in some places, its 

 disappearance from the New Forest cannot be thus explained : for the 

 natural conditions of that district, with its vast moors, oak woods, dense 

 beech groves, old thorns, and thickets of sloe-bushes, have undergone 

 little change during the last five hundred years. 



It seems more probable that the extreme scarcity, or total dis- 

 appearance of the Black-veined White may be due to a succession 

 of wet ungenial summers and mild winters. There are probably also 

 other climatic changes in progress which, though imperceptible to us, 

 may be the cause of the scarcity, or total extinction of this and 

 other species formerly common in the United Kingdom. 



Although the extinction of Aporia cratcegi in England in the near 

 future does not seem improbable, I trust that captures of the species 

 during the coming season, may be recorded from many parts of Eng- 

 land, and that the foregoing observations will be proved to be those 

 of a pessimist. 



Berrjlands, Surbiton Hill : 



February bth, 1887- 



The decadence of Aporia cratcegi in Kent, and its probable cause. — Tho Editors 

 of the Ent. Mo. Mag., in their last number in a note to a query by Mr. C W. Dale, 

 say, "Wo have no reason to doubt that this butterfly (A. cratcegi) still occurs in 

 the usual numbers in the district between Heme Bay and Canterbury." At the last 

 meeting of the South London Entomological Society, the decadence of A. cratcegi 

 in Kent was somewhat fully discussed, and no member of the Society (present at the 

 meeting) had taken tho insect for many years in the localities that some years since 

 produced it in such abundance. As a native of one of the localities (Strood, near 

 Kochester), where it was most abundant (1850 — 186R), I can safely say that it has 

 been exceedingly rare there, if not extinct, for some sixteen years. When I first com- 

 menced collecting butterflies in 1871, I was delighted by a local Entomologist (who 

 had not collected since 1866 or '67, and since deceased) giving me several of our 

 British butterflies, among them a number of A. cratcegi, which he said was one of the 

 most common butterflies in the district. The species, he said, abounded in the larval 

 state on the whitethorn hedges surrounding a number of grazing fields near Strood 

 (almost in the town), their webs being very conspicuous. Of course I searched for 

 it, but in vain, and the only specimen I captured was in 1872 at Caxton in a clover 

 field. Until the end of 1875 I was most energetic and scoured the district for miles 

 around without success. I captured 47 species of our British butterflies in the years 

 1872 — 75 in that district, but never met with more than this one specimen, and have 

 never seen it since. I have been repeatedly over many of its old haunts at the right time. 

 Pupse of the species have been offered occasionally for sale, but only, I believe, by 

 dealers in foreign insects. May I suggest that migration lies at the bottom of the 

 probable cause of the great falling off observed in the numbers of this species ? I 



