328 BAKER: HYDROBIUS FUSCIPES. 
vegetarian in a state of nature I am unable to say, but on dissecting 
tank-reared specimens I have found small crustaceans, such as 
Cypris, inside their cesophagus ; but it is hard to imagine how such 
lively little creatures as these can be obtained in any abundance by 
such, comparatively speaking, slow-moving insects as Hydrobius. 
Whatever the cause, however, it is an undisputable fact that the 
H a 
In colour the beetle varies from light brown (in recently hatched 
specimens) up to a very dark brown or even black. This, however, 
is subject to variation, for many of the Hydrobii which inhabit ponds 
or ditches near to the coast show a tendency to a metallic blue tint. 
This I noticed more especially in the ponds on the banks of the 
Humber to ie east of Hull, and also in a pond on the sand dunes 
near to Cleetho 
Generally podee it is a typically vegetarian beetle, and, 
herever a weed-grown pond is found, there you may be sure to 
n fri gener. 
habits, Helophorus aguaticus. No matter if the pond be covered 
with a continuous covering of duck-weed, stretching from bank to 
bank, a few minutes’ search will, as a rule, discover one, if not both, 
of these creatures. In fact, it is in such ponds as these that they 
thrive best and occur in the greatest numbers, for their great 
enemies, the carnivorous aquatic beetles of the family Dytiscide 
o not, as a rule, frequent ponds in which there are no open 
spaces where they can easily come to the surface to breathe, and 
consequently they are not so much ‘thinned.’ Other enemies of | 
theirs there are, however, in abundance including all such birds 
as ducks, teal, and water-hens, and last, but not least, frogs and 
newts are responsible for numbers of them. Their sluggish habits 
and slow mode of locomotion place them in a very great measure at 
the mercy of these numerous enemies. 
Their legs are formed more for climbing along the stems and 
leaves of water-plants than for swimming, but they can, by rapidly 
working their legs, proceed at a fair pace through the water. As 
a rule, they turn over on their backs when they wish to swim, for 
two reasons. In the first place, being lighter than water, their whole 
necessary for the purpose of respiration is stored between the elytra 
and the pie surface of the abdomen, the beetle elevating the tps the tips 
“Naturalist, ne : 
