MIGRATION AND DISPEES.AL OF INSECTS '. LEPIDOPTEEA, 185 



beginning of September, pass the winter in the south, and then return 

 northward in the early spring to deposit their eggs for the summer's 

 brood, it would give them a much longer active life in the mature 

 state, than falls to the lot of butterflies that hybernate in this region. 

 Whether any of those passing the winter in the south, reach the far 

 north the following season, is yet open to question." Without 

 discussing the doubtful logic of the first of these quotations, except to 

 say that, even if we believed the species did actually reach the south, 

 where it could hybernate, after leaving the northern regions where 

 the autumnal examples were born, we do not understand Avhy it must 

 of necessity return " in spring, by scattered individuals," and we would 

 ask whence, if not from those " passing the winter in the south," Moffat 

 surmises those that " reach the far north the following season " do 

 come. Possibly he believes that not the original emigrants themselves 

 but their progeny reach so far north. The analogy of Pyrameis cardui, 

 Colias edma, C. /(//aZf, and other migrating Pal^earctic species, leads us 

 to suspect that it is the emigrants that reach to the northern limit of 

 the range of the species. It may be well now to consider in some 

 detail the observations relating to the autumnal swarms of this insect 

 that have given rise to the view that a return journey is accomplished. 

 Saunders reports (Canadian Entoiiioloyist, iii., pp. 156-157) that 

 on September 1st, 1871, while driving along the Lake Shore Road, on 

 the borders of Lake Erie, a mile or two south of Port Stanley, some 

 groups of A. arcJiippus, numbering probably hundreds of individuals, 

 which had rested at night on the trees adjoining the hotel at Port 

 Stanley, were gyrating in a wild manner at all heights, some so far up 

 that they appeared but as moving specks in the sky, others floating 

 lower, over the tops of the trees, in an apparently aimless manner. 

 At about nine o'clock the same morning, however, passing a group of 

 trees forming a rude semicircle at the edge of a wood facing the lake, 

 the leaves of the trees attracted attention. They seemed possessed of 

 unusual motion, and displayed fitful patches of brilliant red. On 

 alighting, a nearer approach revealed the presence of vast numbers — I 

 might safely say millions — of these butterflies clustering everywhere. 

 AVhen disturbed, they flew up in immense numbers, filling the air, 

 and after floating about a short time gradually settled again. There 

 appeared to be nothing on the trees to attract them. Reed observes 

 {loc. cit., i., p. 19) that in 1868 the species literally swarmed at 

 Amherstburg, reminding him of a similar occurrence in Toronto about 

 seven years previously. Peabody notes {loc. cit., xii., pp. 119-120) 

 that at Racine, Wisconsin, during the first week of September, 1868, 

 A. archijqjits appeared in great numbers and gathered in several 

 swarms about trees in the vicinity. The day was cloudy, but without 

 rain. Shortly after noon the swarms seemed to gather and settle 

 upon an oak tree in the garden, the southern aspect of which they 

 covered to such an extent that the green of the leaves was quite 

 obscured by the brown of the wings of the butterflies. They remained 

 until after nightfall, but were gone in the morning. Another observer 

 on September 19th, 1868, reports that at St. Joseph, Missouri, he saw 

 " millions of these butterflies (A. archipjnts) filling the air to a height 

 of three or four hundred feet for several hours, and flying from north 

 to south." Thaxter writes {loc. cit., xii., p. 38) that while spending the 

 winter of 1875-1876 in Apalachicola, Florida, he found a swarm of 



