HYDROCA.\rPin.-E—PARAPONYX. 289 



Hydrocharis morsus-rana\ and some of the species of T'ota- 

 mogcton. Curtis says on Stiritiotrs cdoiihs, and Ilofmann 

 Trapa nvtans. In a habitation formed of threads of silk 

 joining together stems or leaves of the water plants and 

 comiDletely submerged, usually at some depth, in the water. 



Of its habits Mr. Buckler says: "Night and day, at 

 intervals varj-ing from one to three minutes apart, the larva, 

 holding to its weh by the anal legs, rapidly undulates its 

 body upwards and forwards with considerable vigour and 

 energ}-, while the three hinder segments appear motionless ; 

 this intermittent movement lasts about twenty-one seconds 

 at a time, and is followed by a period of rest — lunger, that is 

 for two or three minutes — when the larva is quiet, and shorter 

 when it is feeding, at such times not exceeding one minute. 

 That this energetic undulation is connected with the respira- 

 tion of the larva is evident from the fact that the branchial 

 filaments are then all in strong action, for instead of radiating 

 as they do in repose, they become depressed a little, and 

 point forwards in the direction of the head. 



The smaller larvffi ate only the green substance from the 

 leaves, thus bleaching them ; but the larger ones ate com- 

 pletely through the leaves, cutting out circular pieces. The 

 excrement was ejected with such great velocity that it was 

 carried about an inch outside the opening of the silken 

 residence." 



Pupa half an inch long, rather slender, widest from behind 

 the thorax, whence the abdomen tapers to the rather blunt 

 tip ; head rather square ; eyes large and prominent ; wing, 

 antenna, and leg-cases well developed, the latter extending 

 free from the eighth to the end of the twelfth segment ; only 

 the spiracles on the sixth, seventh, and eighth segments are 

 distinguishable, but these are large, circular, and projecting 

 considerably, like knobs or warts from the sides ; at first the 

 pupa is unicolorous, of a delicate yellowish-flesh tint, but as 

 it approaches maturity the wings appear, of a dark grey- 



VOL. IX. T 



