STATES OF INSEcTS. (Zgg.) 73 
of the great water-beetle (Hydrophilus piceus) was long 
ago described and figured by Lyonnet?; and amore de- 
tailed account of it has since been given by M. Miger?. 
In form it somewhat resembles a turnip when reversed, 
since it consists of a pouch of the shape of an oblate 
spheroid, the great diameter of which is three quarters 
of an inch; and the small, half an inch, from which rises 
a curved horn, about an inch long and terminating in a 
point®. The animal is furnished with a pair of anal 
spinners, which move from right to left, and up and down, 
with much quickness and agility: from these spinners a 
white and glutinous fluid appears to issue, that forms the 
pouch, which it takes the animal about three hours to 
construct. The exterior tissue is produced by a kind of 
liquid and glutinous paste, which by desiccation becomes 
a flexible covering impermeable to water; the second, 
which envelops the eggs, is a kind of light down of great 
whiteness, that keeps them from injuring each other. The 
tissue of the horn is of a silky nature, porous and shining, 
and greatly resembling the cocoons of Lepidoptera. 'This 
part, contrary to what Lyonnet supposes, appears calcu- 
lated to admit the air, the water soon penetrating it when 
submerged. At its base is the opening prepared for the 
egress of the larva, when hatched, which is closed by 
some threads, that, by means of the air confined in the 
cocoon or pouch, hinder the water from getting in 4. 
This nidus does not float at liberty in the water till after 
the eggs are hatched, the parent animal always attaching 
* Lesser, L. i. 300. 
> Annales du Muséum, xiv. 441. © Lesser, L. i. t. i. f. Xvi. 
« Miger, Ann. du Mus. ubi supr. Comp. N. Dict. d Hist. Nat. xv. 
482—, 
