Fishing with Floating Flies

by Samuel G. Camp

The life histories of the caddis and stone flies, with which the writer does not feel sufficiently familiar to warrant discussion, are very interestingly given by Prof. Vernon L. Kellogg in his book, to which I have previously alluded, "American Insects," a volume, by the way, invaluable to the tentative American dry fly fisherman. (Published by Henry Holt & Company, New York.)

"So it was that my first summer's camping and climbing in the Rockies acquired a special interest from the slight acquaintanceship I then made with a group of insects which, unfortunately, are so little known and studied in this country that the amateur has practically no written help at all to enable him to become acquainted with their various kinds. These insects are the caddis flies; not limited in their distribution by any means to the Rocky Mountains, but found all over the country where there are streams. But it is in mountain streams that the caddis flies become conspicuous by their own abundance and by the scarcity of other kinds of insects.

"In Europe the caddis flies have been pretty well studied and more than 500 kinds are known. In this country about 150 kinds have been determined, but these are only a fraction of the species which occur here. Popularly the adults are hardly known at all, the knowledge of the group being almost restricted to the aquatic larvae, whose cleverly built protecting cases or houses made of sand, pebbles, or bits of wood held together with silken threads give the insects their common name, i. e., case or caddis worms.

"The cases are familiar objects in most clear streams and ponds. There is great variety in the materials used and in the size and shape of the cases, each kind of caddis worm having a particular and constant style of house-building. Grains of sand may be fastened together to form tiny, smooth-walled, symmetrical cornucopias, or small stones to form larger, rough-walled, irregular cylinders. Small bits of twigs or pine needles may be used; and these chips may be laid longitudinally or transversely and with projecting ends. Small snail-shells or bits of leaves and grass may serve for building materials.

"While most of the cases are free and are carried about by the worm in its ramblings, some are fastened to the boulders or rock banks or bed of the stream. These fixed cases are usually composed of bits of stone or smooth pebbles irregularly tied together with silken threads. In all the cases silk spun by the caddis worm is used to tie or cement together the foreign building materials, and often a complete inner silken lining is made.

"The larvae within the cases are worm- or caterpillar-like, with head and thorax usually brown and horny-walled, while the rest of the body is soft and whitish. The head with the mouth-parts, and the thorax with the long strong legs, are the only parts of the body that project from the protecting case, and hence need to be specially hardened. At the posterior tip of the abdomen is a pair of strong hooks pointing outward. These hooks can be fastened into the sides of the case and thus hold the larva safely in its house.... The caddis worm crawls slowly about searching for food, which consists of vegetable matter. Those larvae which have fixed cases have to leave it in search of food. Some of them make occasional foraging expeditions to considerable distances from home. Others have the interesting habit of spinning nearby a tiny net fastened and stretched in such a way that its broad shallow mouth is directed upstream, so that the current may bring into it the small aquatic creatures which serve these caddis-fishermen as food. The caddis flies live several months, and according to Howard some pass the winter in the larval stage.

"When the caddis worms are ready to transform they withdraw wholly into the case and close the opening with a loose wall of stones or chips and silk. This wall keeps out enemies, but always admits the water which is necessary for respiration.... When ready to issue the pupa usually comes out from the submerged case, crawls up on some support above water and there moults, the winged imago soon flying away. Some kinds, however, emerge from the water. Comstock observed the pupa of one of the net-building kinds to swim to the surface of the water.... The instant the creature was free from the water the wings expanded to their full size and it flew away several feet.... The time required for the insect to expand its wings and take its first flight was scarcely more than one second; certainly less than two. As such caddis flies normally emerge from rapidly flowing streams which dash over rocks, it is evident that if much time were required for the wings to become fit for use, as is the case with most other insects, the wave succeeding that which swept one from the water would sweep it back again and destroy it.

"The adult caddis flies ... are mostly obscurely colored, rather small moth-like creatures, that limit their flying to short, uncertain excursions along the stream or pond shore, and spend long hours of resting in the close foliage of the bank.... They probably do not live long."

Of the stone flies Prof. Kellogg writes as follows: