490 FOOT. [VoL. XIV. 
degree of moisture and temperature. It has proved best to 
keep them as nearly as possible in a temperature of 21 C., 
avoiding extremes of heat or cold. Cocoons are deposited at 
all hours of the day, as fresh ones are found at all hours, vary- 
ing from 4 A.M.to 6 p.m. They are undoubtedly deposited 
also at night, as I have found cocoons containing 2-, 3-, 4-, 
and 6-celled stages at 5 A.M. In midsummer, the early 
morning hours have proved most favorable for finding the fresh 
cocoons; but when the nights are cold, better success has been 
obtained later in the day. At the height of the breeding season 
from 2 to 10 fresh cocoons have been found daily in a pot 
containing 100 worms, and the number of cocoons found in 
these pots leads me to surmise that the worms deposit cocoons 
very often. 
Technique. —The cocoon is placed in a small watch-glass 
under distilled water, and separated from its slime-tube by 
grasping the long end of the slime-tube with a pair of small, 
toothed forceps, and with a fine needle tearing it from the cocoon 
sufficiently to allow the latter to be pushed out. The cord- 
like projection of the cocoon is then held by the forceps, and 
with a sharp pair of scissors about one-sixth of the cocoon is 
cut off at its opposite (blunt) end, the albumen with the eggs 
being then readily pushed out by pressing the cocoon with the 
needle. The amount of the cocoon that can safely be cut off 
is easily determined, for the position of the eggs is readily 
observed under the dissecting microscope. When the cocoon 
is first deposited, it is difficult to separate it from its slime- 
tube, for the former is then so soft that the two appear almost 
fused. At this stage it is sometimes advisable not to attempt 
to separate them, but to cut through both with sharp scissors, 
removing the albumen by pressure. The eggs are set free 
from the albumen by teasing the latter with very fine needles. 
The albumen of the freshly deposited cocoons is so adhesive 
and elastic that it is very difficult to separate it from the eggs 
without injury to the latter. It gradually loses these proper- 
ties, however, until by the time the cocoon contains odécytes, 
2d order, the albumen can be readily cut or torn by the needles, 
allowing the eggs easily to be set free. To avoid losing the 
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