222 THE CANADIAN ENTOMOLOGIST. 



Bimargi?ialis and vitti/?ons stand together by liaving the costal region 

 of primaries from base to the t. p. line pale, discoloured ; an even streak 

 which does not invade the cell or the ordinary spots. 



Next comes a longer series of species, in which the orbicular is open 

 to the costa and is more or less distinctly V shaped. The costal region 

 may or may not be paler than the ground colour, and there may or may 

 not be a black filling in the cell around the spots ; the open orbicular 

 distinguishes yi?;-///^//^, costata, co?ifusa, crenulaia, exsertistigma^ Icetula^ 

 discoidalis^ niger, emarginata and ineta. In addition to the character of 

 maculation all these species have the thoracic crest distinctly marked, and 

 furrowed or divided centrally. 



This latter feature is also shared by 7?iirabiiis, which has contrasting 

 discoloured ordinary spots, and ine/egafis, which has not much maculation 

 of any kind. 



All the rest of the species are more depressed or flattened, without 

 obvious thoracic tufting, and the orbicular is always completely defined, 

 never open to the costa. 



Placida differs from all of those in this series by having an obvious 

 median shade line. 



Scopeops and variata have a bluish underlay, which appears through- 

 out the wing and gives them a characteristic mottled appearance. 



Then comes a series of species with somewhat elongate, subparallel 

 wings, with rounded or stumpy outer margins. They are all variable, and 

 it is difficult to divide them on exclusive characters. I include Jiefascia, 

 dtianca, alteniata, alcatidola, Bel/ragei, ajichocelioides^ brii7ineipennis and 

 cupidissima. 



Last of all come trigona and sambo, two species with shorter, 

 broader, triangular wings, in which the apices are well marked and the 

 outer margins are oblique. 



Rhyiichagroti's gilvipennis, Grt. 



Our only species representing the yellow-winged forms of the old 

 world. It occurs ihroiighout the Northern United States and Canada, 

 extending west to Calgary and into British Columbia, but not reaching the 

 Pacific Coast. It extends northward to Anticosti and into Labrador and 

 probably throughout the boreal region. It is a close ally of the European 

 and Abiaiic c/iardynii, 13dv., and was at one lime supposed to be the 

 same. There is not much variation in the numerous specimens I have 

 seen. 



