The Biology of the Roach 63 
The data gathered in 1916 indicated that July was the 
natural period of death for the roaches, both those kept 
for observation and for the population at large. By 
August 2nd, all those in the jars had died, and simul- 
taneously the adult roaches at large in the building bad 
disappeared. 
The housewife has a justifiable abhorrence of these 
creatures when they are adult; when thousands of 
nymphs infest her home, either she sees them not, or 
she bothers not about them, but the adults are con- 
spicuous and at once arouse her wrath. Forthwith she 
hies her to the nearest chemist and gets some good 
exterminator; two weeks later she will in good faith 
gladly tell the merits of ‘‘X¥YZ’’ paste, and one cannot 
convince her that she spread her poison just at the time 
when the roaches were dying a natural death, and that 
they would have disappeared at that time of the year 
regardless of whether or not she spread her paste. 
Number of egg cases deposited.—The female deposits 
during her lifetime from one to four egg cases. Fifty- 
five roaches were confined for the purpose of getting 
data on oviposition. The following table presents the 
data. 
Egg cases. Females. 
1 8 
2 19 
3 19 
4 9 
The egg cases are not dropped as soon as they are 
formed, but they are slowly pushed out from the abdo- 
men, and after they have been carried about for two or — 
three days, they are finally dropped. I am inclined to 
suspect that the duration of the period of waiting is 
determined in greater part by inherent physiological 
