JOURNAL OF ENTOMOLOGY AND ZOOLOGY 151 
most Instantly. Then they usually leave the swarm and go sailmg 
away, the male above doing the flying, the smaller female hanging 
limply underneath. After a rather short time they break away and 
the separated individuals depart. When copulation is prolonged, 
the male becomes tired and the pair rest on the upper surface of the 
leaves as describeti ante. 
May 28, 1914, 7:15 p. m. — Today at this hour, Eriocera is 
swarming in immense numbers out over the river. Copulation was 
observed many times. The male grasps the female in the swarm 
and they fly away, the male above doing all the active work of 
flight, the female below, entirely passive. The antennae of the 
male are directed straight ahead and slightly divergent; the legs 
hang downward; the wings vibrate rapidly. The female hangs 
downward with the legs hanging limply; the wings nearly horizontal 
and motionless. The dead weight of the female keeps pulling the 
male ciown toward the water and often both fall into the river. As 
a rule copulation ends before the male is exhausted. The male 
opens his forceps and the female drops straight downward for a 
foot or so exactly like a parachute released from a balloon. If the 
pair are near the water at the time of separation the released female 
drops into the water, the male flying away. The released male 
darts upward again and back into the swarm. The female slowly 
flies away, usually upstream, sometimes downstream, presumably to 
lay her eggs; she does not stop for swarms that she may encounter 
but if she meets these swarms she will make a wide detour in order 
to avoid them. Often a second male will seize a female alreaciy in 
copulation and the three will come tumbling down into the water 
together. 
In a very few cases the female is the active partner and succeeds 
in pulling the male where she wills although much smaller. In 
other cases the female before being released from the male flutters 
the wings violently as though impatient. Copulation occurred com- 
monly this evening and it is probable that the hours of twilight are 
the usual ones though several were found mating on leaf-surfaces 
during the afternoon as mentioned earlier. It may be that these 
matings started in the air and upon the approach of exhaustion the 
