64 
To suppose that ordinary migration or spread of species would 
explain the difficulty is out of the question, since I have already 
shown that it is contrary to the habits of the species to travel on 
to uncongenial soils, where, even if pressed to do so by excess of 
numbers, they would he unable to exist. 
Nobody will of course venture to suppose that there has been a 
special creation for this small tract of country, and we are therefore, 
as I think, driven to the conclusion that the species in question 
have occupied this suitable ground, from the tune of the close of 
the Post Glacial period at least, and that they have remained 
unchanged in form, and even in colour, all through the changing 
conditions of life occurring during the upheaval of the fen valley, 
and the consequent alteration of our coast line, and particularly 
those caused by the change from the saline influences of the 
neighbouring sea, to those of a warm inland district. 
One slight change of habit is apparent, due doubtless to the 
increased temperature. All these species were out on June 4th, 
desertella in swarms ; and a week later lotella was common and 
albicolon getting worn, while at the same time albicolon and 
desertella were just beginning to appear at Yarmouth, and the 
other species were not to be found there till a fortnight later, July 
being their time of appearance on the coast. 
It would now be very interesting to ascertain whether Euholia 
lineolata, Leucania littnmlis, Agrotis valUgera, cursoria or ripce, 
all of them inhabiting our present coast sands, were also still to 
be found in what may probably have been their ancient haunts. 
A small scrap of additional evidence has come to hand since 
this paper was written. In a list of Lepidoptera, contributed by 
Mr. De Grey to our county list, is the name of Gelechia pictella, 
a more delicate species than either of those I have mentioned, and 
one which almost exclusively frequents coast sandhills, found also 
at Brandon. 
December 20th. 
Since the paper read at the last meeting was written, I have 
received some valuable confirmatory evidence. The Bev. II. S. 
Marriott, of Wickham Market, and Kev. II. Williams, of Croxton, 
inform me that they find Euholia lineolata commonly on the grassy 
heaths, and Agrotis valUgera flying in Lucerne fields round Thct- 
