Skinner, Ernest B. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume XV, Part I (1904)
Vorhies, Charles T.
Habits and anatomy of the larva of the caddis fly, Platyphylax designatus, Walker, pp. -123 PDF (5.1 MB)
HABITS AND ANATOMY OF THE LARVA OF THE CADDIS-FLY, PLATYPHYLAX DESIGNATUS, WALKER. C. T. VORHIES. The larvae of the caddis-fly, I1latyphylax designatus Walk., fare found in great nilLibers in a certain group of ceid springs on the southern shore of Lake AVingra, near Madison, Wisconsin. There are several other large springs about the shores of the same lake, but the larvae are not abundant in any of the others l and in some are not found at all. The conditions found in the group inhabited by the larvae are as follows: cold water in abundance throughout the year at a temperature of 80 C. never freezing in the most severe winter weather: plenty of clean rather fine sand, with numerous coarser particles; many larger stones, under which the larvae lie hidden during the daytime,; Water-cress, Nasturtium Officinale, in great quantities, and some water-milfoil, Myriophyllum, on which plants the larvae feed. A few larvae may be found during the day under the denser clusters of water-cress, where there is little light, but not much evidence of feeding by day may be seen. As the loose stories under which the larvae a-re hidden are often at a distance of five or six feet or even more from the food plant, and as the in- testine is always found distended with food in these specimens, the conclusion is at once forced upon us that they feed almost entirely at night. The fact that during the day the larvae in dishes in the laboratory cluster in the darkest shelter obtainable lends support to this conclusion. When a loose stone is lifted under which dozens of larvae are gathered, what at first appears to be a mass of sand begins to heave and niove and soon resolves itself into a number of individual larval cases, each being labori- I I
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