150 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



Co., Oxford, May 21, 1904 (Britton). New York, Herkimer Co., 

 Trenton Falls, collected by Osten Sacken; Dolgeville, May 16, 

 1914 (Alexander); Fulton Co., Northampton, May 28, 1914 

 (Alexander) ; Tompkins Co., Ithaca, May 1-10, 1913, (Alexander 

 and Lloyd). Pennsylvania, Wyoming Co., North Mt., June 7, 

 1898 (Johnson). Maryland, Plummer's Is., April 12, 1908 (Bar- 

 ber) : April 21, 1907 '(McAtee) ; Jackson's Is., May 22, 1913 

 (Shannon and Barber) ; Cabin John Bridge, May 16, 1909 (Knab). 

 Virginia, Fairfax Co., May (Banks). Illinois, collected by Kenni- 

 cott. 



The following supplementary notes on the swarming and mating 

 were made at Northampton (Fish-house) on the Sacandaga River, 

 Fulton Co., N. Y., at the boom of the International Paper Mills. 



May 27, 1914 — This afternoon across the river from our camp 

 this species was exceedingly abundant. They were there in untold 

 myriads and at every step arose in clouds from under foot or from 

 the leaves of choke-cherry on which they rested. They sat on the 

 leaves with the head directed away from the observer ready to take 

 instant flight. A few were in copulation on the leaves, but from 

 observations made it seems probable that mating begins in the air 

 and the pair seek a support later. Toward twilight this insect may 

 be found in great numbers in company with many kinds of caddice- 

 flies and a few may-flies. Seven p. m. — Eriocera swarming in great 

 numbers, from 50 to 200 in a swarm facing the gentle westerly 

 breeze (downstream). One big swarm near the shore numbered at 

 least 2000 individuals and covered a vertical height of at least 50 

 feet, the base of the swarm being about 15 feet above the surface of 

 the water. Coming back across the boom it was found that several 

 of these great swarms had fused so that one almost continuous 

 swarm of thousands of individuals was formed, extending from 

 shore to shore of the river. A great number of specimens were 

 secured by a few sweeps of the net. When danger approaches, the 

 swarm either mounts into the air overhead or else retreats before 

 the breeze, never going sideways or advancing. Out over the land 

 in the small swarms, copulation was observed several times. The 

 males in the swarm dart rapidly at the females and seize them al- 



