92 THE BUTTERFLIES OF NEW ENGLAND. 



of butterflies, should be carefully noted. In general the line of separation 

 of the Canadian and Alleghanian faunas is placed further south by Allen 

 than by Verrill and Packard. The accompanying map of faunal areas 

 will show that according to my view it should be carried even still a little 

 further south, and if the line in passing through our district presents 

 o-reater irregularities than in the case of the others, it is due solely to the 

 influence of the Connecticut and Hudson Rivers in carrying northward 

 along their bottom lands many butterflies of the Alleghanian fauna. The 

 line, as I would trace it, starts from the gulf of Maine near the mouth of 

 the Kennebec and runs at first parallel to the coast so as to include Sebago 

 pond, but recedes slightly from the shore near the forty-third parallel, 

 until it strikes the northern border of ^Massachusetts south of Monadnock, 

 curving around which it turns sharply to the north, crossing the Connecti- 

 cut River near Ascutney Mountain, turning again southward and following 

 the course of this stream until near the middle of Massachusetts, when it 

 beo-ins to curve westward until it has swung around the higher elevations 

 of the Berkshire Hills in southern Massachusetts, again passes to the 

 northward along the valley of the Hudson, and turns once more to the 

 westward just before reaching Lake George. 



But the line as we have here traced it, should by no means be regarded 

 as a fixed one. It is rather the centre of a broad belt whose south- 

 ern margin limits many of the Alleghanian species, while other species 

 find their northernmost extension at various points within the broad belt ; 

 its northern borders mark the ordinary southern limits of the species 

 of the Canadian fauna, which may, however, extend to this middle line or 

 even beyond. The northern limit of the belt would correspond very 

 closely with the dividing line of the Canadian and Alleghanian faunas as 

 marked by Verrill. As will be seen, it starts from the bay of Maine in the 

 immediate vicinity of Mt. Desert, passes to the northward with an easterly 

 inclination up the valley of the Penobscot nearly to the New Brunswick 

 border, then turns to run south-westward parallel to the coast along the 

 margin of the more broken hilly parts of the state, in aline approximately 

 south-west from Mattawamkeag, Me., to North Conway, N. H., inter- 

 rupted, however, as it crosses the Androscoggin, by a deep bay reaching 

 the New Hampshire border ; skirting the White Mountains at their southern 

 limits, it passes barely north of the lake region of New Hampshire, then 

 turns northward again on approaching the valley of the Connecticut so as 

 to strike the vicinity of St. Johnsbury ; here it crosses the river, turns 

 southward and follows the course of the Green Mountains as far as their 

 hisfhest elevations in north-western Massachusetts, turning around which 

 the line returns due north, past the whole length of Lake Champlain, 

 and then with a slight easterly bend crosses the St. Lawrence not far 

 above Quebec ; here it turns quickly to the west again, following the near 



