range spots_. This character
will at once distinguish this from the next species (_W. Album_). On the
under side of the hind wing is a _broad band of orange_, having a _row of
black spots on its inner edge_.

The _caterpillar_ is green, with four rows of yellow spots. It feeds on the
sloe.

The _butterfly_ comes out about the end of June or in July. It is generally
a very rare insect, but is occasionally taken in great plenty in certain
spots. The Rev. W. Bree, writing to the _Zoologist_ from the neighbourhood
of Polebrook, North Hants, says, "_Thecla Pruni_ is very uncertain in its
appearance. In 1837 it literally swarmed in Barnwell and Ashton Wolds; I do
not scruple to say that it would have been possible {143} to capture some
hundreds of them, had one been so disposed; for the last few years it has
appeared very sparingly indeed." It has also been found in the following
localities:--Overton Wood; Brington, Huntingdonshire; and Monks Wood,
Cambridgeshire.

* * * * *

THE WHITE LETTER HAIR-STREAK. (_Thecla W. Album._)

(Plate XII. fig. 3.)

This is very much like the last in appearance, and has often been mistaken
for it by inexperienced eyes. The _points_ of difference are--on the upper
side, the absence of the orange band at the hinder edge of the hind wings,
and the presence of a _bluish grey circumflex line at the inner angle_;
here also is sometimes a _small orange dot_;--beneath, the _orange band
forms a series of arches_, bounded on the edge nearest the root of the wing
_by a clear black line_ instead of the rounded black spots seen at this
part in _Pruni_.

The _caterpillar_, which feeds on the elm, is wood-louse shaped; pea-green,
barred with yellow; head black. May be beaten off elm trees in May.

The _butterfly_ appears in July, and is found in various situations,
sometimes flying high up round elm trees, sometimes descending to bramble
hedges, or fluttering {144} about in weedy fields a foot or two from the
ground. It was formerly a much rarer insect than at present, and now its
appearance in any given locality is a matter of much uncertainty. Mr. J. F.
Stephens writes as follows to the _Zoologist_:--

"For eighteen years I possessed four bleached specimens only of _Thecla W.
Album_, having vainly endeavoured to procure others, when, in 1827, as
elsewhere recorded, I saw the insect at Ripley, not by dozens only, but by
scores of thousands! and although I frequented