64 Trans. Acad. Sci. of St. Lous 
conditions, and in a lesser part to the temporary en- 
vironment, i. e., the dropping of the egg case is to some 
degree postponed until a place is reached where it may 
be deposited amid proper surroundings of moisture, tem- 
perature, seclusion, etc. 
Age of females at time of first oviposition—Records 
were kept of the lapse of time between the date when the 
female roach went through the final moult and became 
adult, and the day when she deposited her first egg case. 
These intervals were 8, 11, 11, 13, 14, 15, 18, 19, 22, 
and 24 days. 
Thus the normal females in this series never deposited 
before they were 11 days old (the 8-day individual was 
virgin), and one deposited her first egg case at the age 
of 24 days. Averages, however, are of no significance 
in this case, since in all probability egg laying is closely 
connected with mating, and no records were kept of the 
time that elapsed between mating and oviposition. This 
oviposition occurred from the third week in May to the 
middle of June, but no correlation could be detected 
between the age of the female at first oviposition and 
earliness or lateness in the season. 
Records were also kept on the number of days that 
elapsed between the various egg cases for 35 females. 
‘As mentioned above, each fémale deposits during her 
life-time from one to four cases; these, however, do not 
follow in rapid succession, but at the following intervals: 
Days Days Days 
Roach between between between 
Number Ist & 2nd 2nd & 3rd 3rd & 4th 
1 6 15 — 
2 12 ae Se 
3 8 oe as 
4 11 ae ou 
