NYMPIIALINAE : P0LY(;UN1A GRACILIS. 361 



of the luAver lialf or slightly aljovc this, \vith broad base, slightly llattened summit, 

 and nine strongly compressed, very slightly elevated, pellucid, vertical ribs which in- 

 crease in height from the middle of the egg to the summit with increasing rapidity, 

 but at the highest are only .025 ram. high. The surface between them is flat, 

 smooth, crossed by exceedingly tine lines .02 mm. apart, which traverse and striate the 

 ribs. The termination of tlie ribs at the summit leaves a free central space .25 mm. 

 in diameter, in the centre of which the micropyle is .1 mm. in diameter. Height of 

 egg, .85 mm. ; bi-eadth, .8 mm. 



Distribution (19 : 7) . Excepting in New England, this butterfly has 

 rarely been met with, l)ut it must have a wide range through British 

 America, for it wat> taken by Mr. Dall on the Yukon River, Alaska, fifty 

 miles above Nowikakat ; there is a specimen in the Cambridge Museum 

 from Great Slave Lake, and I captured it at Dog's Head near the middle 

 of Lake Winnipeg. Strecker also speaks of it as obtained by GefFcken 

 in the Athabasca region, Jenner Weir records it from Moose Factory, 

 Hudson Bay, and Fletcher found it at Nepigon north of Lake Superior, 

 and at Sudbury north of Georgian Bay. He also tells me that it has been 

 taken in Montreal.* 



In New England it has only been reported from a few northern locali- 

 ties. It has been taken at Jefferson, N. H., and on the road to Wilson's 

 Mills in Maine (Packard). It is sometimes tolerably common in the 

 higher valleys of the White Mountains, the region where it is best known, 

 where, however, it occupies a district distinctly lower than P. faunus ; for 

 instance, on the road from Fabyan's to the Base, I found faunus far more 

 abundant on the portion above Twin River farm (elevation about 2500 

 feet) than in that below, while the reverse was true of gracilis. The 

 latter files, however, higher than this, and has even been taken on the 

 summit of Mount ^\ ashinjjton. 



History and habits. We know very little of the history of this rare 

 insect, the early stages being quite unknoAvn. Efforts one spring to obtain 

 eggii from females placed under muslin upon willow were unsuccessful 

 although tried with several different specimens. From their times of 

 appearance and condition, we may judge that so far as seasons and broods 

 are concerned the history is identical with that of faunus, and it was this 

 circumstance mainly that once led me to think it a dimorphic form of 

 that abundant species. The butterflies hibernate and are to be found 

 flying as early as anyone visits the mountains and until at least the 11th 

 of June. They appear again in the latter half of July and fly till hiberna- 

 tion. The specimen taken in Alaska was found June (i ; that on Lake 

 Winnipeg August 5. 



P. gracilis is less active and vigorous than P. faunus, is rather more 

 shy and keeps company with its kind less ; the last, perhaps, a mere conse- 

 quence of its rarity. In other respects it is wholly like it, alighting like 



* Butler credits it to Mendociuu Co., Cal., of etiquette. .See .Jourii. Linn. soc. Lond., 

 but certainly by an error of determiuatiou or zoo!., xvi: 467. 



