54 
cold-storage vaults for these and other experiments. The folloTving- 
temperatures were tried on two lots of eggs, some freshly laid and 
others partly developed. After the periods mentioned the respective 
lots of eggs were removed and the percentages hatching noted, as 
shown in the table: 
. Table XYI. — Effeci ofloirer temperatures on eggs. 
Treatment. 
First series — eggs with trace Second series — brown ring 
of brown ring. well formed. 
34° F. for 48 hours i About 90 per cent hatched.. Practically all hatched. 
34° F. for 24 hours, then 27° F. for 72 hours.! AboutnOper cent hatched..! Do. 
34° F. for 24 hours, then 27° F. for 24 hours. About 25 per cent hatched..! About 33 per cent hatched, 
then 18° F. for 72 hours. 
It is evident from the figures in the table that eggs which are 
further developed are less susceptible to the effects of cold, and that 
the eggs are able to withstand short periods of cold better than longer 
ones. Althouo'h there was onlv about twelve to eighteen hours differ- 
ence in the age of the eggs in the two series, the proportion hatching 
from the older one was from 10 to 50 per cent greater. Some of the 
larv^ hatching from these eggs were kept to see if they had been 
weakened in any way by the cold, but all seemed as healthy as larva? 
hatched under normal conditions. The shock to the egg in the experi- 
ments must have greatly exceeded that caused by any sudden cold 
spell to wliich they might be subjected in the early spring. 
EFFECT OF ATMOSPHERIC COXDITIOXS. 
Moisture and dryness seem to have no effect on the time required 
for development. A number of eggs submerged under water shortly 
after they were laid and others placed in a desiccator dried by sul- 
phuric acid, hatched in practically the same length of time as a check 
lot under normal conditions. This resistance to atmospheric conditions 
is no doubt du^ to the thick. imperA'ious. chitinous eggshell which 
prevents the transpiration of water vapor to any extent. 
EFFECT OF SrBMERGEXCE OX EGGS. 
In the spring a good proportion of the eggs are deposited on young 
corn plants: they are often subjected to wetting by heavy rains which 
occur during this season of the year, and at times are washed down 
into the "bud" where the rain water accumulates. To ascertain how 
much submergence under water the eggs are able to withstand, a 
number of experiments were tried in the laboratory. On June 4. Si 
freshly laid eggs were submerged in six lots for periods varying from 
twenty-five minutes to four hours. Of these only 2 failed to hatch, 
and these were not in the lot which was under water longest. At 
another time a card with 8.5 eggs attached was placed in a vial of 
