1134 THE BUTTERFLIES OF NEW ENGLAND. 



to tlie end of Fcbriuiry belong to the form ariadne, though at the very out- 

 set, according to a hiter conimuuicution to Mr. Edwards, a few worn speci- 

 mens of amphidusa may be found in the early part of November. The new- 

 brood of butterflies wliit^h appears in iVIarcii is made up of kecwaydin ; 

 while those coming subsequent to this belong to tiic form amphidusa, of 

 which there are at least two broods. To use Mr. Edwards's translation of 

 Mr. Boll's paper, Mr. Boll continues as follows : — 



"If we compare the specimens we liml a steaily increase in intensity of coloi- [and 

 in size] from April to .June ; tiie orange-red ijecomes more fiery and extends in tlie male 

 over tlie whole npper snrface of secondaries, leaving [sulphur] yellow only the costal 

 margin of primaries, while the black marginal band becomes broader and broader. 

 Through the influence of the sun the whole orange npper side becomes iridescent, with 

 a violet hue, as in the European species, C. myrmidone. This is particularly noticeable 

 during life, and is very brilliant, but gradually fades in dried specimens. The whole 

 underside changes from greenish-yellow to [sulphur] yellow. . . . The efl'ect of tempera- 

 ure is in perfect harmony with the steady increase in size and intensity of color." 



Here, then, during the year which begins in November, we find several 

 broods, the first consisting of ariadne, the second of keewaydin and the sub- 

 sequent broods of amphidusa. the insect bridging over the intervening space 

 probably in the caterpillar state or jjossibly in part also by the pei'sistent 

 life of a few butterflies. "If either form," says Edwards, "appears in any 

 degree out of its season, it is not in sufficient numbers to invalidate the 

 rule. The species here is truly polymorphic and seasonally so." 



Just what the sequence is in the extreme north Mr. Edwards could prol)- 

 ably tell us from the mass of observations wiiich he has obtained in many 

 yeai's, but at tlie time of the last connected account he has given us of this 

 species, tiie northern yellow type was still considered a distinct species. 

 Apparently, iiowcver, in tlic Rocky Mountains the earliest brood of the 

 season consists of the form eriphyle, which, on higher elevations at least, 

 replaces altogether the form ariadne of the south. This is followed iu 

 June by a more abundant brood, and in July and August by another 

 brood, and these two broods are restricted, according to Edwai'ds, to "kee- 

 wavdin, and intergrade up to the paler variety of eurytheme, but a few 

 individuals arc taken which show a tendency to vary in the direction of ari- 

 adne." But if I understand aright his presentation of the facts and those 

 given by Mr. Cockerell, there are combined with these, toward the cold 

 season, a certain percentage of eriphyle, a form which in the north would 

 appear to be found at the two extremes of the cold season, while the more 

 brilliantly colored forms belong to the hotter part of the year. But, accord- 

 ing to Mr. Edwards, there is the same sort (but j)resumaiily not the same 

 degree) of difl^erencc between the autumn and spring forms of eriphyle as 

 there is between ariadne and eurytheme, so that he regards the form eri- 

 phyle itself as seasonally dimorphic, the difterence being that tlie spring 



