58 THE CANADIAN ENTOMOLOGIST. 



ences relied on by Mr. Edwards," he refers to my plates and text in 

 Vol. 2, B. N. A., 1875 ; and I should here say that when those plates 

 were published, my information as to all these forms was very meagre, 

 and very few examples were in collections. As to Gigas, I had never 

 seen the male, and the only one known to be in any collection was the 

 type specimen in the British Museum. So my figure was given from a 

 drawing made for the purpose at the Museum, and it was badly coloured, 

 and inadequately represented the under side of the hind wing, which in 

 this genus is usually the most characteristic part of the insect. As to the 

 female, it was copied from the best of three poor examples which I had 

 from Mr. Crotch, and these were the only examples of the species in 

 American collections. The figures of Californica and Idima are well 

 done. I intend before Vol. 3 closes to re-figure Gigas, and to give all the 

 stages I may then be able to ; and all the stages of the other two except 

 the pupse. As to Nevadensis, it is not a fourth species, though I let it 

 stand alone, not knowing to which of the three it was intended to apply. 

 It was impossible to decide from the very poor figure or the description. 

 I rather thought it was meant to represent Californica., but Dr. Holland 

 is confident that it was intended for Gigas. If this is so, apparently the 

 name of the Vancouver species should be Nevadensis., as the catalogues 

 date it 1867, whereas Gigas dates 1868. But Mr. Butler has informed 

 me that Felder antedated by one year his species. It was really not pub- 

 lished and on sale till 1868, and subsequent to the issue of the Cat. of 

 Satyr., which figured and described Gigas, and so Gigas would have 

 priority. A vast deal has been learned respecting these species since 

 1875, and they are now by no means uncommon in collections. 



That Mr. Elwes is som.etimes willing to allow that habitat and habits 

 of flight are a factor in determining species, as well as distinct geographi- 

 cal ranges, appears in what he says of Ivallda, on p. 469 : — " I was in- 

 clined to think Ivallda was a pale form of this ( Chryxus), as I could not 

 see any distinction but that of colour. Prof. Owen, however, who has 

 taken both, assures me that the habitat and flight of the two differ ; and, 

 as the geographical range oi Ivallda, which, so far as we know, is confined 

 to the Sierra Nevada, in Placer County, California, and about Lake 

 Tahoe. is quite distinct from that of Chryxus, which is not known to 

 occur in the Rockies in the U. S., it may probably he looked on as a con- 

 stantly distinct species." This is really sensible and to the point. Mr. 

 Bruce had written me from Colorado, last summer, after spending a day 



