1G0 
HALF HOURS WITH INSECTS. 
[Packard. 
The only possible way to study the aquatic insects is to 
keep them in glass jars and bowls, where their habits can be 
carefully studied. An aquarium may thus be improvised 
which will last for several weeks without care, though it is 
better to add a few water plants, such as the water cress, the 
Valisneria, Callitriche, Duckweed and other plants, to keep 
the water oxygenated. By stocking the aquarium with the 
larvae and pupae of certain neuropterous insects at the time 
when the winged forms are most abundant, the immature 
forms can easily be kept long enough for us to determine the 
winged species into which they pass. In the autumn, as 
cold weather and short days keep us indoors, much profit 
and solid amusement may be gained by these studies of 
pond life within the house. Even in winter after the snow 
is on the ground, one can break through the ice of roadside 
ponds and with a small net capture nearly all the insects we 
have spoken of in this number, and keep watch upon their 
habits, and study their anatomy, with the aid of the needle 
and lens. He can also turn to the lower forms, such as the 
water fleas, rotifers, infusoria and rhizopods, with which the 
waters teem winter and summer, and find, with a few dips 
of the net, material for weeks of observation and study. 
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