EUPLOEINAE: ANOSIA PLKXIPPUS. 727 



the [)resont B[)ccie8, the second to a closely allied form from Jamaica, 

 possibly only a variety and not a distinct form, "^riie confusion in the 

 names was brought about, however, mainly by Fabricius, who first dis- 

 tinctly misapplied the name of plexippus to the Asiatic species alone and 

 redescribed the American form under the name of archippus. As there 

 can be in this case no doubt whatever that the species was first described 

 by Linne under the name plexippus, and as at the time he did not con- 

 found it with any other form, there can be but one conclusion ; which 

 is that the species should bear the specific name of plexippus. 



Natural distribution- This magnificent butterfly is more widely dis- 

 tril)utcd than any of our species, if we except those which also occur in 

 Europe and have perhaps been introduced thence. If the insect from 

 Brazil described by Cramer under the name of crippus is really identical 

 with our New England species, then it ranges over the whole North 

 American continent from Atlantic to Pacific, as far north as the annual 

 isotherm of 40*, and over that portion of South America laying east of the 

 Andes and north of Kio, including also many and perhaps all of the West 

 India Islands as well as Bermuda. There are specimens in the British 

 Museum and the Museum of Comparative Zoology, from Cuba, St. Do- 

 mingo, and St. Thomas and from Canto Gallo, Pernambuco, Lagoa Santa, 

 Corcovado and Para, South America, and it has recently been recorded 

 by Berg from Patagonia which it probably has reached by way of the 

 slopes of the Andes, though it is unknown in Chili. The probable nat- 

 ural limit of its northern distribution is not far south of the boundary line 

 dividing the Canadian and Alleghanian faunas ; at least so far as eastern 

 America is concerned. By natural limits I mean the limits within which 

 the insect is to be found undergoing its natural transformations year after 

 year without annual extinction during the cold winter. This boundary in 

 the east may be said to be probably not far from the northern parts of 

 Connecticut and Pennsylvania or about the northern limit of the Allegha- 

 nian fauna, though it doubtless extends further north along the river 

 valleys of southerly flowing streams, and may be annually extinguished in 

 the higher and colder regions further south, such as the Catskills, and even 

 the Alleghanies. In the interior it probably extends further north than 

 near the coast. 



Annual excursions. For, a review of all the facts of its occurrence in 

 the north leads me to believe, what indeed was first suggested many years 

 ago by Riley, that in the northern districts of its range this species 

 will annually perish during the colder season, when the butterfly hiber- 

 nates, and be replenished by excursions northward from the borders of 

 its natural territory, so as in the latter part of the season to be found very 



* This general statement does not here Mountain district though it is meant to cover 

 necessarily include the whole of the Rocky the greater part of it. 



