. Lessons in nature study. Nature study. 66 NATURE STUDY water, so that oxygen may be brought in and the exhaled car- bonic acid gas carried away. Other Brook Insects.—The young stone-flies, May-flies and caddice-flies are the insects of the brook most certainly and easily found. On the surface of quiet pools may be seen water- striders and whirligig beetles, but these may more certainly be found on ponds, and are described among the " pond ; You may find, perhaps, clinging to the rock-bed of the stream where the water is shallow but flowing swiftly, many small black worm-lik
. Lessons in nature study. Nature study. 66 NATURE STUDY water, so that oxygen may be brought in and the exhaled car- bonic acid gas carried away. Other Brook Insects.—The young stone-flies, May-flies and caddice-flies are the insects of the brook most certainly and easily found. On the surface of quiet pools may be seen water- striders and whirligig beetles, but these may more certainly be found on ponds, and are described among the " pond ; You may find, perhaps, clinging to the rock-bed of the stream where the water is shallow but flowing swiftly, many small black worm-like animals (fig. 39, a) holding firmly to the rock by one end while the rest of the body stands nearly upright in the water wav- ing about as the swiftly running water strikes it. These are the young or lar- VEe,of the black fly, a small jet black, hump-backed, two-winged fly (fig. 40). The black-fly is a biting fly of more vicious disposition and more efiTective biting ability than the mosquito. Take some of ifhese squirming black larvae to the school-room and examine them in a watch-glass of water with a magnifier. (They cannot be ikept alive long in quiet water). Note the odd shape of the body. Note the sucker at the posterior end of the body, by wliich the larvse holds fast to the rock despite the swift current. Note the two fan-shaped organs attached to the head, which arc composed each of fifty hairs rising from a short, stout process; these organs are waved about in the water, sweeping microscopic water organisms into the mouth. You may find among these black-fly larvae a number of odd little cornucopias (fig. 39, b), fastened to the rock by their lower end. From the upper end of each cornucopia a pair of tiny tufts of short filaments (tracheal. Fiq-. "9. I^arv:e (</) and pupcc (b) of the ' Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these ill
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