LIFE HISTORY AND HABITS: THE EGG. 49 
During the past 3 or 4 years we have been able to secure records 
on the incubation period for many eggs in different parts of the 
country. 
Observations on the length of the egg stage under out-of-doors con- 
ditions were made at Youngstown, N. Y., in 1905, but are not as 
extended as could be desired. Nevertheless, the following data by 
Mr. Johnson are of interest: 7 eggs deposited from June 8, a. m., to 
June 9, a. m., had by June 15 developed as follows: 
2 larvee hatched, but still in egg cavity. 
1 larva escaped from eggshell. 
1 larva feeding at pit of fruit. 
1 larva in short burrow near egg. 
2 eggs unhatched. 
These figures in a general way would indicate a period for the egg 
stage of 6 to 7 days. 
Forty-six eggs deposited June 15 from 1 to 7 p. m., on June 20 at 
2 p.m. were found to have developed as follows: 
20 unhatched. 
15 larve hatched, but still in egg cavity. 
11 larve in burrows, one-fourth to one-half inch from egg cavity. 
This indicates an egg stage of approximately 44 to 5 days. 
Forty-three eggs deposited June 24 were found on June 30, at 6 
p- m., to be in the following condition: 
6 eggs unhatched. 
16 larvee in burrows, about one-eighth inch from egg cavity. 
11 larvee in egg cavity. 
6 larvee just burrowing out of egg cavity. 
4 larve feeding at pit. 
The egg stage with this lot is from 5 to 7 days. 
At Washington, D. C., in 1905,.Mr. A. A. Girault made many 
observations on the length of the egg stage, as shown in Table XII. 
The eggs were kept in the insectary, and the temperature on the 
whole averaged considerably higher than at the same time out of 
doors. The longest period of incubation was 5 days, in the case of 
30 eggs deposited on May 18, and the shortest period was 2 days and 
15 hours, for a lot of 22 eggs deposited on June 14. The average 
incubation period, as based on the total number of egg days, is 3.77 
days. (See also Table XIII.) 
17262°—Bull. 103—12——4 
