30 Trans. Acad. Sci. of St. Louis. 
The greatest length of time spent in copulo was by A 1, 
1 day 5 hours and 15 minutes. The shortest time spent in ~ 
copulo was by A 4, 8 hours and 30 minutes. The average 
time spent in copulo for the eleven cases (excluding A 4 
which was accidentally severed) was 21 hours and 20 5/11 
minutes. 
In every case the pairing was done during the night, 
the following morning finding them in copulo, in which 
condition they would remain throughout the day, sep- 
arating some time during the following evening. Both 
male and female were active from the time when the wings 
had spread until they had mated. Wherever possible 
they were given to mate very soon after hatching to avoid 
an expenditure of excessive amount of vitality and in- 
juring themselves through their activity, which perhaps 
might have caused earlier death. 
As I have already shown, the males, after leaving the 
females, lived from 6 to 12 days, and retained their orig- 
inal activity for perhaps one or two days. Then for some- 
time they would grow less active, remain almost station- 
ary on the wire or twigs in the cage, and would only be- 
come somewhat active when handled. Soon they became 
too aged to even cling to the wire. We would then find 
them lying on the bottom of the cage, only moving when 
irritated. Soon the wings assumed a vertical position and 
the insects remained for the most part motionless, resting 
on one side of their abdomen and on one wing. When 
irritated they could just barely move the wings, and pres- 
ently would appear dead. My test for ascertaining 
whether the organism was still alive was to gently move 
the wings back into their normal position and see if they 
still had the power to assume the vertical position. Thus, 
we see the slow senescence and death of the male. 
In the females we find the insects ovipositing on the 
same day, or at the latest, one day after the termination 
of copulation. After three days of ovipositing we usually 
find the female dead, death, no doubt, being due to ex- 
haustion from the task of egg laying, for, in the greater 
