232 NATURAL HISTORY OF AQUATIC INSECTS CH. 



favourite resort of a number of Snails, Leeches, 

 Polyps, and other animals. Paraponyx also occurs 

 on Anacharis (Buckler). 



De Geer found a Paraponyx larva walking on the 

 leaf of Stratiotes, under water. He placed it in a 

 vessel, and next day found that it had cut out a piece 

 of the leaf, and made a sheath for itself, bringing 

 the two concave sides together, as nymph&ata does 

 with Potamogeton. The larvae feel greedily on the 

 leaves of Stratiotes. The sheath allowed the water 

 to enter freely, and the larva was completely wetted. 

 In some cases, the bases of the leaves were merely 

 tied together with silk, and not cut. The larva 

 grows to upwards of an inch in length. It is of a 

 pale transparent or yellowish green. The head is 

 brown, deeply cut out behind, and capable of being 

 retracted into the prothorax. The antennas are 

 longer than in most caterpillars, and several-jointed. 

 Along the sides of the body are found transparent 

 branchial filaments supplied by special air-tubes. 

 Some of the filaments are single, others spring three 

 or four together from a common point. There are 

 six tufts on some segments, eight on others, not 

 counting the single filaments ; the prothorax has none. 

 The branchial filaments are passive, and unlike those 

 of the Ephemera, cannot be separately moved. 



Though the branchial filaments are fixed to the 

 body, the body performs regular respiratory move- 

 ments, like those of a Caddis-worm or a Chironomus 

 larva. Buckler tells us that night and day, at in- 

 tervals of from one to three minutes, the larva rapidly 

 undulates its body up and down, the. hinder end, by 



