182 I June, 



THE DECADENCE OF BRITISH BUTTERFLIES, WITH SUGGESTIONS 

 FOR A CLOSE-TIME. 



{Ahstr acted from a Presidential Address delivered before the West Kent 

 Natural History, (Sfc, Society on February 22nd, 1893). 



BY ROBERT McLACHLAN, F.R.S., &c. 



Early in January, 1887, I received in an editorial capacity a query 

 as to whether Aporia crntcegi still existed on this side of England.* 

 Now for many years previously my special attention had been 

 occupied and absorbed by another Order of insects, and, as the 

 sequel proved, my knowledge as to the then-existing conditions of 

 certain British Butterflies had become distinctly rusty. My reply to 

 the query was that I had no reason to doubt that the insect still 

 occurred in the district between Heme Bay and Canterbury. This 

 locality was chosen in particular, because it had been one of the known 

 haunts of the species, and it was there that early in July, 1858,t I met 

 with it in the greatest abundance. From their condition the Butter- 

 flies had evidently been out for some time, and a search along the 

 hawthorn hedges showed a large quantity of the empty pupa-skins. 

 I may here remark that, although this Butterfly has never been con- 

 sidered an injurious insect in this country, it is often so considered on 

 the Continent in consequence of its damage to various fruit trees. 



This simple query, and the ignorance and innocence shown in the 

 reply to it, were the means of bringing forward a mass of interesting 

 communications, showing that the insect had disappeared from all its 

 usual haunts, not only in Kent, but practically all over England, and 

 that, in fact, it had been waning since about the year 1865. 



That Aporia cratcegi, like many other British Butterflies, had a 

 much wider distribution formerly than recently, there can be no 

 question ; but possibly it never occurred either in Scotland or Ireland. 

 In the old works of the last century it is mentioned constantly, and it 

 must be remembered that w^orkers in those days were few, whereas at 

 present every corner of these islands has its eager explorers, either 

 residents or visitors. So long ago as 1828, we find J. F. Stephens^ 

 stating that in 1810 he saw it in plenty in Coombe Wood, Wimbledon, 

 and in the following year at Muswell Hill; and that Mr. Haworth 

 informed him it used to abound constantly at Chelsea, but had 

 disappeared. So at one time it was a London insect, but it probably 

 ceased to be such before the vast majority of Entomologists now living 



* Ent. Mo. Mag., xxiii, p 214. f Entomologist's Weekly Intelligencer, iv, p. 125. 

 { Iliu.st. Brit. Ent., Haust , 1, p. '2. 



