take care to ensure a good s

H 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 moths, and as many of them have

their wings
thickly covered with hairs, this resemblance is sometimes very marked. The
larvae (caddis-worms), being eagerly sought as food by many fish, and having very soft bodies, make for themselves cases. Some of these cases are made from small sticks, some from little pieces of stone or sand, and some from a mixture of all of these substances. As these cases resemble such small pieces of rubbish as are frequently found in streams, care should be taken that they do not get into the hatching trays containing ova.
Many of the water beetles, and

practically all of their larvae, will attack the

ova; they should therefore be carefully excluded from the hatching trays. As there
are about 114 different species of beetles in the family of
_Dytiscidae_ alone, my readers will appreciate my reason for not

attempting to enumerate
them. It will be a sufficient warning to state the fact that they