THE WATER CABINET, 133 
the dragon-fly, and do not go through their metamor- 
phosis well without such food. 
The imago is a handsome creature, with strong hooked 
claws, furnished with amber hairs, which, under a lens, 
resemble very closely the claws of a crab. The elytra 
are beautifully tinted with rich green and bronze, and the 
divisions of the head and thorax separated from the abdo- 
men by sharp, whitish lines. Small fishes make the best 
diet for this beetle ; but as this food fouls the water, it is 
best to keep them in clear jars, with a few pebbles and 
weeds, and once a week remove them to another vessel, 
to be fed. This plan preserves the brightness of the 
beetle jar, and prevents the annoyance of effluvia. 
Hyprovus Picrus.—This is the largest of our native 
aquatic beetles, and, with the exception of the stag- 
beetle, it exceeds in bulk any other species of indigenous 
Coleoptera. It is common in the brooks and ponds in 
southern counties, but becomes rare as we travel north- 
wards. In the larva state this is a rapacious and blood- 
thirsty insect, and of so destructive a character as to 
deserve its French name of ver-assassin. In that early 
condition it resembles a large soft worm, of a somewhat 
conical form, provided with six feet, and having its large 
scaly head armed with two formidable jaws. The head 
moves with such freedom in all directions, that it can 
readily seize small shell-fish and other mollusca floating 
on the surface, without altering the horizontal position of 
the body maintained in swimming; and it is even bent 
backwards, and devours its prey more conveniently by 
using the back as a kind of support. These larve swim 
