330 BAKER : HYDROBIUS FUSCIPES. 
woven threads, and is about 4 mm. by 3 mm., flattened and 
rounded at one end. he other bud, the last one finished, 
terminates in an irregularly shaped flap, by which the cocoon is 
fastened to the blades of grass, etc. Sometimes this loose flap is an 
inch and a quarter in length, and often as many as three cocoons 
are attached to one blade of grass. Each beetle makes three or four 
cocoons, at intervals of about. a fortnight. In a 
few days the larve (Fig. 4) emerge from the eggs, 
portions of water-plants, and after resting there a 
short time enter the water, and suspending them- 
selves by their peculiar anal processes to the 
surface film of the water, gyrate about after the 
style of a Chironomus, only always keeping the 
anal segment, with the spiracular openings, above 
the surface of the water. This anal segment is 
very flexible, and they can crawl sideways, 
horizontally, or vertically, without altering the 
exposed tip. These motions are evidently for 
the purpose of securing the small animals upon 
which they, at this early stage, feed. When not 
engaged in performing these ‘ figures of eight,’ they 
n 
hatched its head is much wider than its body, but whereas the 
former grows but little, the latter soon begins to assume more equal 
proportions, and at the end of a week, at which time the diameter of 
the head and the body are about equal, they measure about 4} mm. 
in length. After this, though their heads grow very little, their 
bodies increase both in width and length, until after about three 
months spent in the larval state, they attain a total length of about 
12 mm., and are ready to pupate. They have at all times a most 
voracious appetite, and, if food is at all scarce, show very strong 
cannibalistic propensities, and frequently, after placing as many a5 
dozen together in one tank, have I found at the end of about 
a wees only one or two fine, well-fed ones and fragments of the 
Naturalist 
