JOURNAL OF ENTOMOLOGY AND ZOOLOGY 151 



most instantly. Then they usually leave the swarm and go sailing 

 away, the male abov^e doing the flying, the smaller female hanging 

 limply underneath. After a rather short time they breais: away and 

 the separated indiv'iduals depart. When copulation is prolonged, 

 the male becomes tired and the pair rest on the upper surface of the 

 leaves as described 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 down 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 already in 

 copulation and the three will come tumbling dov/n 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 



