18 
suffice. But in such a case the temperature is more or less variable, and 
the embryo may be started in its development only to be checked by re- 
newed cold. When kept at a uniform low temperature, after having 
once been cooled, development is imperceptible, and when afterward 
exposed to the proper hatching conditions, the resultant worms will 
prove more vigorous. If possible the temperature should never be al- 
lowed to rise above 40° F., but may be allowed to sink below freezing 
point without injury. 
When small lots of eggs are to be wintered, they may be placed in 
ordinary boxes in the cellar, care being taken to observe the precautions 
noted above as to ventilation, humidity, and temperature. They should 
also be protected from rats, mice, ants, and other vermin. But where 
great quantities are to be stored, it will be well worth while to construct 
special hibernating boxes, where the requisite conditions may be regu- 
lated with nicety and precision. 
A great object should be to have them hatch uniformly, and this is 
best attained by keeping together those laid at one and the same time, 
and by wintering them, as already recommended, in cellars or hiber- 
nating boxes that are cool enough to prevent any embryonic develop- 
ment. They should then, as soon as the leaves of their food- plant have 
commenced to put forth,* be placed in trays and brought into a well-aired 
room where the temperature averages about 75° F. If they have been 
wintered adhering to the cloth on which they were laid, all that it is 
necessary to do is to spread this same cloth over the bottom of the tray. 
If, on the contrary, they have been wintered in the loose condition, they 
must be uniformly sifted or spread over sheets of cloth or paper. The 
temperature should be kept uniform, and a small stove in the hatching- 
room will prove very valuable in providing this uniformity. The heat 
of the room may be increased about 2° each day, and if the eggs have 
been well kept back during the winter, they will begin to hatch under 
such treatment on the fifth or sixth day. By no means must the eggs 
be exposed to the sun’s rays, which would kill them in a very short 
time. As the time of hatching approaches, the eggs grow lighter in 
color, and then, if the weather be dry, the atmosphere must be kept 
moist artificially by sprinkling the floor or otherwise, in order to enable 
the worms to eat through the egg-shell more easily. They also appear 
fresher and more vigorous with due amount of moisture. 
It will be found that eggs which have been subjected to great cold 
during the winter will require a longer time in their incubation than 
those which have been kept at a higher temperature, and it is also true, 
as has been intimated above, that when the atmosphere in which the 
eggs have been retained has been excessively dry it will require con- 
~ *Too much stress can not be laid on the importance of beginning the rearing of 
worms as early as possible, so that the excessive heat of summer may be avoided. — 
Beginners are very apt to delay sending for eggs until after the leaves have put out, 
and there is not only more danger of the hatching of the eggs in transit, but the 
worms will be maturing during very warm weather, 
