354 



PHYSICAL GEOGRAPHY. 



Mountain region, and probably most of the country farther north. In the 

 northern half of the district it is uncommon, but in the extreme south 

 exceedingly abundant. The most northern known localities are Bruns- 

 wick, Waterville, and Norway, Me.; and in New Hampshire, Isles of 

 Shoals (not common), Suncook (not common), Milford (very abundant), 

 Walpole, and Plymouth. 



24. A7-gj'nnis Aphrodite God. In New England this is one of our 

 commonest butterflies, but it is wholly absent fi'om the White Mountain 

 region, where it is replaced by the next species. 



25. Argynnis Atlantis Edw. Abundant through all the cooler parts of 

 Canada, and very closely limited southwardly by the annual isotherm of 

 45°, only surpassing it in elevated regions and along mountain chains. 

 In New England it is probably common everywhere north of the isotherm 

 of 45° maximum temperature for the spring months, but is really abun- 

 dant only in the White Mountain district, where it wholly replaces A. 

 Aphrodite. Other New Hampshire localities are Thornton, Shelburne 

 (Faxon, Minot), Littleton (Sanborn), Jefferson (Scudder), and even Sun- 

 cook (Thaxter), Dublin (Fa.xon), and Milford, very rare (Whitney). 



26. Brenthis Myrina Herr.-Schaff. This butterfly is found in nearly 

 equal abundance throughout New England, in the valleys of the White 

 Mountains, or by the sea-coast. 



27. Brenthis Montinus Scudd. [Plate A., Fig. i]. The geographical 

 range of this insect has been sufficiently indicated in the first part of this 

 paper, in the discussion of the sub-alpine zone. Very little can be added 

 to what has already been published concerning the seasons of this insect. 

 It has been found from July 21 to August 18. Specimens captured August 

 2 had well developed eggs; others taken August 11 were "in good con- 

 dition." It is therefore probable, from analogy with the other species of 

 the genus inhabiting New England, that the butterflies first appear in the 

 middle or latter part of June, and lay their eggs about the middle of 

 August; that these hatch at once, and that the embryonic caterpillars 

 hibernate, reviving sufficiently in the spring to undergo their changes 

 and appear on the wing in June. Perhaps, however, some of these cater- 

 pillars become lethargic and transform later, so as to appear on the 

 wing in August (while the June butterflies are laying their eggs), for 

 fresh individuals have been captured on August 11. Should observers 



