12 
From this we see that it is possible to prevent attack 
by turning the eggs down to an ascertained depth, at 
which, although the tenant may hatch out, yet if the 
ground is in a natural state the insect cannot penetrate 
it. If the earth is cracked, of course the deep crevices 
admit air, and alter the state of the case.* 
The Locust egg will hear freezing and thawing and 
soddening in water, hut the date of hatching, or rather 
the length of time between its deposit and the appear¬ 
ance of the young Locust out of it, has been found to 
vary according to the variations of temperature, from 
which it has been inferred that the egg requires a 
certain amount of heat to develop it, but that this 
amount may be equally healthily conveyed by a short 
time of much warmth, or a longer time of cooler 
weather. 
Eggs have hatched at localities in the Northern 
States where the maximum temperature during the 
spring had rarely risen to 50°, and never exceeded 58° ; 
and from the experiments carried on by different ob¬ 
servers it appears that at a 
Uniform temp, of 85°, the number of days required 
for hatching was 81. 
60. 
116. 
From these experiments we have proof with regard 
to one kind of insect that the development of the 
embryo in the egg may be retarded or entirely checked 
for a time by states of temperature or situation, but 
yet that (within certain limits) the vital powers con¬ 
tinue, and when the eggs are put in favourable circum¬ 
stances the embryos within will develop, and the 
temporary chilling or burying will only have delayed 
(not saved us from) the appearance of the young 
* This information is mainly taken from the Report of the 
Entomological Commission of the U.S.A. Government, 1877. 
