PERLIDAE
Imitation Perlidae, or Stone-flies, are more used in the North in wet-fly
fishing than by the dry-fly fisherman of the South.
The best known species is the Stone-fly proper, but this fly does not
seem to abound in the South, though I have found isolated specimens at
Heathfield in Sussex on two occasions.
This fly is therefore omitted, and the Willow-fly and the Yellow-Sally
only are described.
Perlidae, unlike _Diptera_, have four wings. As, however, the anterior
wings cover the posterior when at rest, it is as a rule only necessary
to make the imitation with one pair of wings.
This posterior pair of wings in the Perlidae often materially changes
the colour of the anterior pair when they are at rest. Thus in the
Willow-fly, though the anterior pair of wings are of a brownish colour,
they appear of a dark slaty hue when the fly is seen crawling about. An
illustration of natural fly is given on Plate I.
WILLOW-FLY (_Leuctra geniculata_, Steph.).
This fly comes on late in the season. In September and October it is
taken freely by the trout and grayling. It is similar in shape to the
Stone-fly of the North.
This fly has almost always been made buzz. Ronalds mentions in his _Fly
Fisher's Entomology_ that it may be made with wings, but does not say
anything about their position. I do not think that the hackle fly is a
really good imitation of the natural insect, and it is quite possible to
put the wings of the imitation in the same position as those of the
natural fly.
It will be seen that there are on Plate II. three illustrations of the
imitation Willow-fly. One of these has its wings in the position of
rest, the manner of dressing which I have described in a previous
chapter.
The other, which has its wings partially spread, I owe to a suggestion
from Mr. G. E. M. Skues.
The posterior pair of wings are put on first, and the anterior
afterwards. As the mode of procedure is practically the same as in the
Blue-bottle, with the addition of another pair of wings, I need not
enter into further detail.
The Willow-fly, when it falls on the water, has its wings sometimes in
one and sometimes in the other of these positions.
_Body._ Light brown fur from water-rat, ribbed with narrow gold tinsel.
_Hackle._ Ginger.
_Wings._ Darkest starling's quill feathers. The wings should be made
narrow.
_Hook._ Nos. 00--1, new size.
(Illustrated, Plate II.)
THE YELLOW SALLY (_Chloroperla grammatica_, Poda).
This fly appears in May and June, and though it is said to be
occasionally taken by trout, does not seem to be relished to any great
extent by them. The wings should be placed one over the other as in the
illustrations of the imitation fly given on Plate II.
_Body._ Light brown water-rat's fur, ribbed with yellow silk.
_Tail._ Two brown fibres from pheasant's wing.
_Hackle._ Partridge hackle, dyed olive.
_Wings._ Quill feather of white hen, dyed olive.
_Hook._ Nos. 1--2, new size.