66 THE ENTOMOLOGIST. 
which occurs at Llanfairfechan, that at the time I did not 
recognise it as the same species. It is a most difficult insect 
to detect, as it mimics very closely (as indeed also does the light 
variety) the rock on which it rests. The variety occurring at 
Bettws-y-coed is a somewhat larger insect, and is very much 
suffused with dark grey or black, and is, | find, remarked upon 
by Guenée, who says in his ‘ Histoire Naturelle,’ vol. ix. p. 464, 
““(uelques individus sont de gris-cendre, d’autres, et ce sont les 
plus ordinaires, d’une couleur d’os un peu jaunatres, avec les 
franges un peu plus rougeatres. Une femelle prise dans la 
Lozére par M. Bellier, est presqu’entiérement envahie par des 
atomes noirs, comme certaines variétes de Bisetata.” 
It occurs at Bettws at a greater elevation than at Llanfair- 
fechan, and on one of those Welsh hills where high winds, with 
heavy rains, and cold misty days seem to be alternate states of 
weather. I do not know whether these ungenial climatal con- 
ditions be the cause, but this darker forn) seems to me to be a 
more robust (if the term be admissable) type of insect attaining 
in certain individuals, and possibly averaging, a greater linear 
expansion than its light-coloured relative. 
[ have now bred some three or four generations of each 
variety, and have been surprised to find how true each keeps to 
the parent type.* 
Some little time ago I wrote upon the subject to the Rev. J. 
Hellins, sending him specimens of each, and stating the main 
facts, viz., that each variety, as far as my experience and that of 
Mr. Capper went, was confined to its own locality; that the suc- 
cessive generations of each were true to the parent form; that, 
on the contrary, though differing inter se as some of the Acidalie 
do, I could see no specific difference. Mr. Hellins wrote to me, 
saying, that unless some recognisable difference could -be 
detected in the egg or larva state, he should consider them 
merely varieties of one species, and he suggested I should 
forward larvee to Mr. Buckler. This I did, and I believe they do 
not differ from the larva of A. contiguaria, as described by him 
(Hi. M. Mo 1i1., 69). 
* Mr. Sidebotham, who has suecessfully bred this species for the last year or 
two, tells me he occasionally gets a darker-coloured brood. If now we may look 
upon this as a “reversion,” it tends to bear out the hypothesis that the darker is 
the original form. 
