1332 Rocer C. SmitH 
and downward, an act which is generally seen before copulation. The 
males and the females rubbed their antennae together, and usually the 
males would fly away. Finally a male and a female continued stroking 
each other vigorously with their antennae. Then they walked to a 
position beside each other, facing in the same direction. Then they 
moved their abdomens together, the male bringing his under that of the 
female so that the ventral surfaces of the two were together. The male 
held the abdomen of the female securely. Later they headed in opposite 
directions. Connection continued for twenty-eight minutes. During 
this time the only perceptible movements were a slight waving of the 
antennae and contractions of the abdomens resembling slow peristalsis. 
finally the female became restless and started to fly away, but the male 
held her, even supporting her suspended. After several further efforts 
by the female to break loose, they separated. Each brought its abdomen 
forward and appeared to be eating at the genitalia. The male held his 
genitalia open for five or ten minutes after copulation. 
All other cases of copulation observed also occurred at about four 
or five o’clock in the afternoon. <A pair of C. mgricornis copulated at 
least twice. They emerged on successive days and were put together 
immediately. The female laid about two dozen eggs, which hatched. 
After these eggs were laid the insects were found in copulation. The 
beginning of the copulation was not observed, but the insects remained 
in connection for a half hour from the time when they were first 
observed. After this copulation, several dozen more fertile eggs were 
laid. The evidence of the first copulation was circumstantial but, since 
fertile eggs were deposited, it is not likely that the supposition was 
ungrounded. The second copulation was observed. 
Egg-laying after copulation 
A number of experiments were carried out to determine the length 
of time that elapsed after copulation before the first egg was laid. The 
female whose copulation is described above, began laying eggs the day 
after copulation. Observations show a varying lapse of time, from a 
few hours to six days. The females are fertilized generally soon after 
emergence, but a minimum of three days is required for the eggs to 
develop. If oogenesis is well advanced, fertile eggs may be deposited 
very soon after copulation. 
It was observed in several instances that in Chrysopa oculata, eggs 
formed when the females were unfertilized. The females deposited a 
number of unstalked eges in the vials, as well as some stalked ones which 
failed to develop embryonically. A female that had deposited unstalked, 
infertile eggs, after copulation deposited stalked, fertile ones. 
