23S president’s address. 
Mr. T. Brown of Cambridge. The former gentleman, whose 
practical acquaintance with more branches than one of Natural 
History is well known, was a perfect mine of information on the 
old fen-lands, and was most ready to impart it when questioned on 
any special point, but unfortunately never published any details. 
Mr. Brown’s acquaintance with the Huntingdonshire Fens appears 
to have commenced not many years before their drainage ; but 
I have heard him tell many a curious story of his experiences there, 
and of the resident fen-men, who there, as at Wicken in later 
days, formed collections of the local insects to sell to entomologists 
visiting the district. 
The species already extinct are probably four in number ; but it 
is necessary to use great caution in making this statement ; for 
owing to the inconspicuous appearance of a large proportion of 
moths, their retiring nature, and the irregularity of their appear- 
ance, it is very difficult to ascertain with certainty when they are 
extinct, and we have but recently had jjroof of this. 
The first of the above four species is the Great Copper Butterfly 
( Polyommatus dispar). This is generally regarded as a permanent 
local variety or sub-species of P. ldppothoe , a Butterfly widely 
distributed over the Continent, and of which I exhibit specimens 
from Siberia and from North Germany. Dr. Staudinger, however, 
breaks it up into two species, taking our P. dispar as the type of 
one, to which he refers the hippotlioc of Hiibner, while regarding 
the hippotlioe of Linnaeus as distinct. As to its occurrence in this 
country, Harding, writing in the ‘Entomologist’ of 1883 gays : 
“It had been known and figured in 1792, and about forty'"' years 
ago, Mr. B. Standish took a coloured figure of the Butterfly down 
to Yaxley, and showing it to a man who worked in the Fen, heard 
* This would make the date about 1843, but, as mentioned below, the 
Rev. E. C. Jenkins took the insect in 1829, so that if Harding’s account 
refers to the first discovery at Whittlesea Mere, as he clearly imagines it to 
do, his memory is at fault as to the date, and sixty years would be nearer 
the mark. Possibly Jenkins’ capture may have been the earlier of the two, 
and remained unknown to Jjondou entomologists at the time of Standish’s 
excursion. But the larva was evidently well-known in 1836 (vide Salmon), 
so that Harding’s date must in any case be ten years too late. 
