15 



An idea of the complication of forms may be gathered from the 

 following summary, taken from the writings of Edwards and 

 Scudder : 



(i) There is the usual sexual dimorphism as seen in our E. edusa. 



(2) The female is also dimorphic; there is a pale form. 



(3) The broods, two, three, or four, or even more, differ distinctly 

 from each other generally. 



(4) The sequence of broods in the mountains takes place at dates 

 different from that of the broods in the hills or lowlands, and the 

 broods in the two latter areas are also not synchronous. 



(5) The broods run into each other, as the oval and larval state 

 lasts at most only about three weeks. 



(6) Among such rapid and active insects a commingling of the 

 broods must take place in areas intermediate between the mountain 

 and lowland. 



(7) On the Pacific lowlands the southern yellow form {ariadne) 

 runs up as far as Vancouver Island, while on the other hand the 

 northern yellow form {eriphyle) goes as far as San Bernardino. 



(8) In some parts the distinctions are well maintained. 



(9) In other areas the characteristics of the various forms crop up 

 anywhere ; especially do they do so towards the close of the warm 

 season, when the early spring forms, or perhaps we should say forms 

 approaching them in characters, reappear. 



(10) In all mountainous regions there is an excessive inter- 

 gradation of forms, probably due to the intermingling of those which 

 have been produced at higher and lower levels. 



The variation, then, may be termed sexual dimorphism of ? , 

 seasonal, geographical, crossing of various forms, and climatic. 



In the second box exhibited are short series of a few other 

 species of Eurymus. 



(1) E. edusa, <$ and ?, with var. helice and intermediates, all 

 either captured or bred from specimens captured in this country. 



(2) E. hya/e, $ and ? , from N. Kent. 



(3) E. phicomene, g and ? , from the Alps. A mountain species. 



(4) E. pahc.no, $ and ? , from Lapland and from the Alps. 

 Another northern and mountain species. 



(5) E. electra, £ and ? , and pale var., from S. Africa. Appears 

 almost identical with our E. edusa. 



(6) E. philodice, $ , from Montreal. A species extremely like 

 the eriphyle form of E. eurytheme, and known specially as the 

 " puddle butterfly " from its habit of assembling in groups on damp 

 places in the roads. 



(7) E. erate, <§ and $ , from Japan. 



Also Meganostoma ccesonia, a species of a genus closely allied to 

 Eurymus. 



This genus, Eurymus (or Co/ias), is distributed throughout the 

 northern hemisphere, and has its culminating area in the Himalayas 

 and the hills of India, where the species are numerous and extremely 



