on the genus CoUas. 7 



Colias Olga, Eomanoff. 



Eomanoff, Hor. Ent. Ross., xiv., pi. i., figs. 1 — 4, 1882. 



C. Myrmiclone, var. Led., Ann. Soc. Ent. Belg., xiii., 20. 



C. Myrmidone, var. Caucasica, Stgr., Cat. Lep. Eur., 

 1871, p. 6. 



This fine form was originall}' considered by Lederer and 

 Staudinger as a variety of Myrmidone, but the latter now 

 looks on it as the Caucasian form of C. Aurora ; and 

 Alpheraky, who knows it well in life, says that it is 

 nearer to Aurora than to either Myrmidone or Aurorina. 

 For my own part I think it is an additional proof, if one 

 was wanted, of the difficulty of defining any of these 

 species. Judging from the figure, which represents a 

 male and three forms of female, I see no reason to 

 separate it from Aurora. The larva of both this species 

 and C. Aurorina are said to feed on Astragalus caucasicus. 

 C. Olga is found not uncommonly about Borjom, Achal- 

 zich, Abbastumau, and other places in the mountains of 

 Georgia at 2000 — 4000 feet elevation, and also at Achty, 

 in Daghestan. It flies from the middle of May to the 

 middle of June, and on into July. The females are more 

 often of the white than the orange form, which, according 

 to Lederer, is also the case with C. Aurorina, and to a 

 great extent the case with Aurora. 



Colias Fieldii, Men. 



I was at first disposed to think this species only a form 

 of Myrmidone, but having received several hundred spe- 

 cimens from Sikkim, others from Nepal and all parts of 

 the North- West Himalaya to Hazara, and, through the 

 kindness of M. C. Oberthur, from Ta-tsien-lo in western 

 Szchuen, I find that, though varying much in size and 

 tint, it may be distinguished with almost absolute cer- 

 tainty from Myrmidone by the black band on the hind 

 wings being continued right round the anterior margin, 

 which is not the case in any of my fifteen males of C. 

 Myrmidone. 



Other though less important characters, which alone 

 would not be of much weight, are the greater size and 

 prominence of the black discal spot above, which on the 

 under side is white-pupilled, and the series of black 

 spots below. Some of the specimens from Kashmir arc 

 much smaller and paler in colour, and are probably the 

 first generation. I should be curious to know whether 



