346 PHYSICAL GEOGRAPHY. 



them feeding on the same plant, Carex rigida, by night. This shows 

 that I was mistaken in a belief formerly expressed, that they fed upon 

 lichens. 



CEneis semidea was first discovered about half a century ago, and 

 described by Say from specimens sent him by Dr. Pickering and Prof. 

 Nuttall, of Boston. Very few specimens seem to have been taken since 

 that time, until 1859, when I made my first considerable collections in the 

 White Mountains. I ascended the highest peak on July 8, for the express 

 purpose of finding the butterfly, and secured my first specimen at about 

 a mile from the summit, near the foot-path from the Glen. On ascending, 

 the butterfly became more abundant ; and, although our party hastened 

 over the ground, more than forty good specimens were taken, and a friend 

 even captured seven without a net. Less than a week afterwards, in a 

 little more than an hour's collecting, fifty-nine were taken, for, in its 

 season, this butterfly is exceedingly abundant. 



Dr. Harris gives "June and July" as the season of the flight of the 

 imago, the former date on the authority of Oakes, who found the insect 

 abundant in June, 1826. Undoubtedly this was toward the close of the 

 month. It usually begins to appear very early (the first week) in July, be- 

 comes exceedingly abundant before the middle of the month, and continues 

 until about the second week in August. Mr. Sanborn gives July 4th as 

 its earliest appearance in 1869, and only one more specimen was seen 

 before the 9th, although the weather was favorable. This may serve, I 

 think, as an average date, and the butterflies will best be taken in the 

 second and third weeks in July. They lay their eggs until about the 22d 

 of July, and probably a little later. These are apparently dropped loosely 

 among the sedges, for I could obtain no eggs on the sedge itself from 

 gravid females confined in open kegs, and finally, searching among the 

 roots as a last resort, I discovered a single egg, which, however, never 

 hatched. Caterpillars have been found by Mr. Sanborn, the late Mr. 

 Shurtleff, and myself, nearly full grown, on the 2d of August, and others 

 certainly full grown on August 19. More recently Mr. Whitney has 

 found them " apparently fully grown, under stones." They were unques- 

 tionably seeking a good place to undergo their transformations. They 

 probably transform to chrysalids at once, and hibernate in that state, 

 although it is possible that they winter as Mr. Whitney found them. In 



