116 THE GOLDFISH AND ITS CULTURE. 
ing illustration shows the insect as seen from below when in the 
water. 
There are two or more varieties of this fly that differ in coloring, 
and of smaller size than the one described, though all are extremely 
destructive to the young fish —the one just delineated, more 
especially. 
THE YELLOW-BANDED WATER BEETLE. 
(Dytiscus marginalis. ) 
This rather pretty beetle, lives entirely below the surface of the 
water, never leaving it, except during the night when the air is 
YELLOW-BANDED WATER BEETLE AND ITS LARVA. 
damp or in rainy weather, and then for the purpose of making 
excursions to other localities. The body is of a greenish black 
color, encircled with a brownish yellow band—this feature giving 
it its name, When taken from the water it exudes a milky fluid of 
a most offensive and disgusting odor. The hind legs are shaped 
very much like those of the boat-fly, and serve the same purpose. 
This beetle is very courageous, attacking fish of any size, as jarge 
ones have been caught, into whose flesh the beetle had eaten large 
holes, the beetle itself found in the hole hard at work eating up the 
fish. The larva, which is produced twice within the same season, 
lives and grows upon tadpoles and young fish. 
