District around Maldon, Essex. 38
Taking the butterflies first, it will be found that thirty-
eight occur in the district. This is a very fair proportion
out of a total of sixty-six, which is the number contained in
the British list; but which includes at least two extinct
species, and two, if not more, that occasionally leave their
continental homes and visit British shores. If we further
eliminate extremely local species, such as M. cinxia, E. cassiope,
Thecla pruni, and several others, thirty-eight becomes a very
good total for any single district. It is a total, however, to
which I think it would be difficult to add a single species, as
butterflies almost force themselves on one's notice, and,
except in the case of a very local insect like N. lucina, are not
likely to be overlooked.
Considering the Diurni rather more in detail, we find that
Papilio machaon, Vanessa c-album, V. antiopa, and Arge
galathea are only stragglers. When the first of these was
taken at Maldon, in 1872, I had only just come to live in
that part of Essex, and being imperfectly acquainted with
the marshes that exist round Maldon I hazarded the con-
jecture that machaon might breed in the vicinity; but I have
long ceased to believe in the probability of this. Vanessa
antiopa occurred in the great "antiopa year," when this
butterfly was observed throughout the length and breadth of
the land. The occurrence of a single specimen of Arge
galathea is remarkable, and difficult of explanation. It is an
insect naturally slow on the wing, and generally found in
great numbers where it occurs. It was doubtless a straggler
that visited Hazeleigh only under the compulsion of strong
winds or other irresistible necessity.
The two English representatives of the genus Colias occur,
sometimes in abundance, near Maldon. Why they appear-
and disappear so suddenly has always been a puzzle to
naturalists. That they come over in vast numbers from the
Continent never seemed very probable to me, and the
falsity of this theory was proved conclusively to myself by
the capture of a deformed specimen of Colias hyale at Wood-
ham Mortimer in 1875. One of its wings was so distorted
as to have made it impossible for the insect to have flown
D