. The Cambridge natural history. Zoology. CADDIS-FLIES 483 large funnel-shaped verandah, covered by a beautiful silken net. This larva lives in the rapids of various rivulets, and the entrance to the verandah is invariably directed towards the upper part of the rivulet, so as to intercept any edible material brought down by the water. Several of these larvae, moreover, build their cases so that they form a transverse row on the upper side of a stone; as many as thirty cases may be placed in one of these rows, and sometimes several rows are placed parallel with one another. This same larva has
. The Cambridge natural history. Zoology. CADDIS-FLIES 483 large funnel-shaped verandah, covered by a beautiful silken net. This larva lives in the rapids of various rivulets, and the entrance to the verandah is invariably directed towards the upper part of the rivulet, so as to intercept any edible material brought down by the water. Several of these larvae, moreover, build their cases so that they form a transverse row on the upper side of a stone; as many as thirty cases may be placed in one of these rows, and sometimes several rows are placed parallel with one another. This same larva has the habit of coming out of its case when necessary, and suspending itself in the water—as some caterpillars do in the air—by means of a silken thread. Other members of -the Hydropsychides form tubes or covered ways of silk, earth and mud attached to stones, and in which they can move freely about. Some of the Hydropsychidae have been ascertained with certainty to be carnivorous in the larval state. A species of the genus Hydrofsyclie has been found by Howard ^ to help itself in the task of procuring food by spread- ing a net in the water in con- nexion with the mouth of its case. This net is woven in wide meshes with extremely strong silk, and supported at the sides and top by bits of twigs and ., „'**^^^^r?5*S=:^^^ small portions of the stems of water - plants. Small larvae ^i«- 328.—Case, with head of larva and snare of North American Hydropsy- brOUght down by the current cliid. (After Riley and Howard.) are arrested by this net for the advantage of the larva that lurks in the tube. The breathing organs of the larvae of Hydropsychides are apparently of a varied character, and would weU repay a careful study. Mr. Morton informs the writer that some of our British species of Philopotamus and Tinodes have no gills either in the larval or pupal state, and probably respire by means of modified tracts in the integument. In some of the alhed genera, Polycentropus, the
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
