HYDRACHNA. 
470 
parable Roesel, by whom it is figured in his well 
known work on insects. It is of equal, or even 
superior size to the immediately preceding, which, 
in many points, it seems greatly to resemble; the 
ground-colour however in this is red, with black 
variegations, disposed in a different manner from 
those of the former. It is found, though not very 
frequently, in stagnant waters. 
Among the smaller, or middle-sized Hydrachnm, 
one of the most common is the H: e.vtemlens, which 
is of the size of a very small hemp-seed, and of a 
bright red colour, without any variegations: it is 
extremely nimble in its motions, and always carries 
the hinder pair of legs, which exceed the rest in 
lengih, in an extended posture. 
Hydrachna araneoides ( A cams aquaticus macii- 
latus. Degeer.) is a small species, of a brown co- 
lour, clouded with red, and marked on the back 
by a very large oval patch of the same colour. It 
is found, like the rest, in stagnant waters, and has 
the habit of a young spider. 
Some of the genus are distinguished by a kind 
of cylindric process at the end of the abdomen: of 
this kind is tlie Hydrachna Buccinator. Lin. Gniel. 
(Acarus caudatus. Degeer.) It is a very small 
species, of a dark brown colour, with a large 
rufous patch at the upper part of the body, the 
cylindric process being of a dull yellow. It is a 
native of stagnant waters. 
The eggs of the Ilydrachnae, which are small 
and round, are deposited in flat clusters, some- 
