the pond off their feed through frightening them. After a heron or
kingfisher has been about a rearing pond the little fish will not feed
for a considerable time, sometimes even for days. Notwithstanding their
very evil proclivities, both herons and kingfishers are very
interesting. A kingfisher, if he catches a fish which is a little too
big for him to swallow whole, will knock the head of the fish, which he
always catches by the middle of the body, against a stone, in order to
kill it, or at least to stop it struggling; it might otherwise in its
struggles escape, as the kingfisher can only swallow a fish head first.
There are stories which tell how herons sometimes pluck small feathers
from their breasts and, floating these feathers upon the water, catch
the trout as they rise to it; it is supposed that the trout takes the
feather for a fly. Personally, I do not think that much credence should
be attached to the latter story.

Other birds, usually found on or near the water, are also likely to do
much harm to the ova and young fish. Almost every creature which is
found near the water seems to have a great liking for the ova of fishes.
All the wading and swimming birds are to be dreaded by the fish
culturist. They will, all of them, eat ova in enormous quantities, and
many of them will also eat the little fish.

Besides birds, small larvae of several insects will eat, or at any rate
kill, the ova in considerable numbers. Caddis-worms are among these
larvae which eat ova. This seems to be one of the few cases in which
nature is just, for caddis-worms are taken very readily by even small
trout. Large trout will take them very greedily, cases and all.
Therefore, I should advise the fish culturist to cultivate them as food
for the fish he is rearing, but to be very careful that they do not get
into the rearing boxes or hatching trays when he has ova in them. The
caddis-worms kill the ova by making a small hole in them and sucking
some of the contents out; from this hole some more of the contents
escapes, and as it comes into contact with the water becomes opaque.

Caddis-worms are the larvae of an order of four-winged flies commonly
known as sedges, caddis-flies, or water-moths. The latter appellation is
of course a misnomer, as these flies (_Trichoptera_) have nothing
whatever to do with moths. They resemble moths, however, in that they
have four wings which when at rest lie in much the same position as do
those of mo