MIGRATION AND DISPERSAL OF INSECTS: LEPIDOPTERA . 207 



221) that at West River, Mavyland, about 7 o'clock in the morning, 

 his attention was called to the fact that "' the whole heavens were 

 swarming with butterflies."' There was " an innumerable number of 

 them at all heights, from 100 feet to a height beyond the range of 

 vision except by the aid of a glass. They were flying due south-west 

 in the face of a stiff breeze. Observations upon the flight of 

 individuals, between points of known distances apart, showed that the 

 rate of movement was not far from twenty miles an hour. Where 

 they originally came from or whither they went \vc could not tell. 

 They undoubtedly came from beyond the bay, which, in that place, is 

 fourteen miles across, and they must have been early on the wing. 

 By 11.30 a.m. the numbers had declined, and it was evident that the 

 bulk of the flight was over, but for several days a great many 

 individuals, evidently following the migrating movement, were 

 observed." Two days later (September 25th, 1886) a report from 

 Maryland (Baltimore County) states that a vast multitude of the same 

 butterflies were seen '•' in migratory movement." They were seem- 

 ingly exhausted in flight, and settled on the trees in such multitudes 

 as to give them the appearance of an autumnal frost. Andras reports 

 that in September, 1887, about the heads of the Saskatchewan River, 

 shrubs and small trees were covered with them in countless numbers. 

 In the cool (almost frost) of the evening they could be shaken to the 

 ground in a helpless, chilled condition, but were lively enough when 

 the sun warmed them. He further adds that " the Cree and Blackfeet 

 Indians say the wind from the south brings them there." Another 

 report from Hampton (New Hampshire), by Scudder, states that, on 

 September 2nd, 1888, when only a stone's throw from the water, 

 continuous streams of A. archlppm passed towards the south-west, 

 following the line of the sea-coast, with the wind about north-west. 

 It was calculated that some fifteen hundred passed the observer in a 

 very short time. In 1892, a year in which this species appears to 

 have been exceptionally abundant, in Ohio and Northern Indiana, the 

 following report relating to the appearance of the insect was sent to 

 Imect Life : ''On September 19th, in the afternoon, a multitude of 

 butterflies visited Cleveland on their way south. There were SAvarms 

 upon swarms of them, and, for a while, they completely filled the air. 

 They Avere of the large brown variety of the Milkweed butterfly, and it 

 is supposed that they were started by the storms in the east. Such 

 migrations, although not iinusual in the south and west, are very 

 uncommon in this part of the country." Dr. Neal also reports {loc. 

 (it., v., p. 197) that, on October Ith, 1892, he saw a swarming or 

 migration of A. arcJnppKg, near Okhahoma, Texas, finding "hundreds 

 of these butterflies roosting at 3 p.m. They were as thick as the 

 leaves on the shrubs. At 9 a.m. next morning they took to the air, 

 and, as far as one could see east and west, from -10 to 200 feet above 

 the ground, the butterflies were flying to the south, apparently one 

 every few feet ; often a cloud of several hundreds would pass almost 

 in a solid body, enough to cast a shadow. At 2 p.m. they diminished in 

 numbers and flew lower down. From the best information that could be 

 obtained this swarm extended twenty miles east and Avest, and were in 

 motion steadily soutliAvard from 8 a.m. to 3 p.m. On October 6th, a 

 smaller swarm was seen, from 10 a.m. until 3 p.m." The observer 

 adds that " no one here recollected seeing such a migration before." 



