728 THE BUTTERFLIES OF NEW ENGLAND. 



abundant. Imlced it is not iniprobahlo that it is as regular a migrant as 

 the birds, returning- southward in the autumn. The prinei})le, and, so 

 far as I can see, the only serious objection to this belief is the fact that it is 

 found in such numbers so \ ery far north and has beeu known to occur, in 

 single instances at least, to an immense distance toward the arctic regions. 

 It has not only been found in every nook and corner of New England, 

 but far beyond that ; it is known from Nova Scotia (Jones), Quebec, not 

 common (Bowles) and Ottawa, Can. (Billings), Moose Factory, Hudson 

 Bay (Wier), the northern shore of Lake Su])erior (Agassiz), the l\ed 

 River valley (Dawson), the Saskatchewan country (American entomolo- 

 gist, iii : 102) the north-west territories of Canada (Geddes), and even as 

 far north as the Athabasca country ( Geftcken ) . That the insect might 

 cover New England e^ery summer would be easily belie>ed. But the 

 extreme distance of Moose Factory and the western shore of Hudson 

 Bay from its supposed natural limits renders confidence in these bounda- 

 ries somewhat less secure. Still the facts which we shall give concerning 

 its annual history in New England, together with those concerning its 

 wide exotic extension in recent times will render it more plausible. Few 

 reports have been returned of its occurrence in the Rocky Mountain region, 

 excepting from (\)lorado where, according to Mead, it occurs e-s cry where 

 below the timber line ; but it has also been recorded from western 

 Wvoiniug, Utah and Arizona. It is, moreover, common along the entire 

 Pacific shore as far north as Vancouver Island, was found by Captain 

 Geddes at all points in the "northwest territory," but is rare in British 

 Columbia (Fletcher). It is probable, therefore, that it occupies, at least 

 at times, all the less elevated portions of the region colored on the map. 

 That there is a regular annual southward movement (tf butterflies, as 

 intimated above, is certainly not proven, but the numerous cases in which 

 a southward migration has been obser\ed at the close of the season o\er 

 considerable tracts of territory in different years, tends strongly to the 

 belief that this is the case. Riley was also the first to suggest such a 

 return movement. In a ])aper read before the Academy of sciences of 

 St. Louis, the substance of which was j)ublished in its Proceedings 

 (iii: 273-274) and in the Scientific American for April G, 1878 (see also 

 American entomologist, iii: 100-102), he remarks ''there is a southward 

 migration late in the jirowing season in congTCgated masses and a north- 

 ward dispersion early in the season through isolated individuals."" As re- 

 gards the southward mo\ement in the autumn, he remarks in his paper in the 

 St. Louis Academy's Proceedings, "the newsi)apers in the southwest and the 

 signal officers were constantly reporting tlie })assage from Iowa, Kansas, 

 Missouri and Texas of swarms of the butterfiies during the months of 

 September and October last." These consisted, in every ca*e where deter- 

 mined, of Anosia j)lexippus. A few cases may be cited. 



