PLEBEIUS ARGUS. 191 



Bergstrasser's philonomw is the $ , and his philonome the $ of the 

 small mountain form of argus (aegon). The figure of the $ is darkish 

 blue, with a rather broad and distinct black border to all four wings ; 

 that of the 2 is fuscous in tint, with no orange spots on the upper- 

 side ; the underside is typical of that of the mountain race, with a well- 

 developed orange, submarginal, transverse band, edged internally with 

 a white band. There can be no doubt that this is also the aegidion of 

 Meissner, which he described as a distinct species, and of which he 

 writes : 



I consider that under this name, a butterfly which we meet with in the higher 

 Alpine valleys, e.g., in theUrserenthal, and even on the high Alps, e.g., on the south 

 side of the Grimsel, must be separated from the preceding species (aegon). Tt is 

 certainly very near to aegon, but differs from it : (1) In its small size, in which it is 

 scarcely larger than alsus. (2) The ground colour of the upperside of the <? , which 

 is of a much more violet-blue than aegon. (3) The spots of the underside which 

 show more or less through on the upperside. (4) In the middle of the forewing a 

 black line appears on the upperside. (5) The position and number of the spots on 

 the underside is as in aegon ; but in the S the golden-green points are wanting in 

 the marginal spots of the hindwing. The ? is brown on the upperside, rarely with 

 a slight, dark blue dusting; the border (fringe) dirty whitish-grey ; on the hind- 

 marg n of the hindwing are more or less distinct orange spots and black marginal 

 dots, which show, also, in more restricted dimensions, on the forewing, always, 

 however, more weakly, and often failing here altogether. The underside is brown- 

 grey ; all the spots are more strongly marked, and the marginal spots of the hind- 

 wings have golden-green kernels. 



In the view that this was a distinct species, he was followed by 

 Charpentier and Meigen, the latter of whom, also, figured this 

 form (though not by name) as a variety of "aegon" Herrich-Schaffer 

 gives it as a synonym of " aegon" and Meyer-Dur, in 1851 {Schmett. 

 Schweiz, p. 66), recognised it as the small mountain form of this 

 species, and also as being identical with the philonomus and philonome 

 of Bergstrasser ; Gerhard also placed it correctly. Staudinger seems 

 to have been the first to misplace it as a variety of " argus " (argyrog- 

 nomon) (Catalog, 1st ed., p. 4, 1861), an error in which he has 

 apparently been followed by almost all subsequent authors. Oberthur 

 makes (Etudes, xx., p. 27) this (as many authors have done) a form of 

 argus (argyrognomon), but the description of Meissner is definite. 

 There can be no doubt that the application of this name to any form 

 of argyrognomon cannot be at all justified. This form is also the 

 alpina of Wheeler (and the later Swiss lepidopterists) which he notes 

 as the " usual form of the mountains, not exceeding 23mm., some- 

 times less, w 7 ith rather dark ground colour, occurring very commonly 

 in July and August. 1898, and beginning of July, 1902, at Berisal." 

 It is recorded from the Ganter Bridge, Laquinthal, Alpien, Rossboden 

 Alp (Rehfous), the Steinenthal (Wheeler), the Grammont, Dent du 

 Midi (Muschamp), etc. Our specimens have come from Arolla, the 

 higher valleys above Courmayeur, etc. 



j8. var. killiasi, Christ, " Jahrb. Nat. Ges. Graub.," xxvi., p. 10 (1883); 

 Killias, " Nachtr. Ins. Graub./' p. 5 (1886). — One of the most striking of the 

 Tarasp butterflies, which we may well consider entitled to a special name as a local 

 race. It differs from the type in the striking smallness of the ? , with regard to 

 the 3 , and especially in the colouring of the upperside of the J . Next to the 

 broad white fringe comes a broad black band, which on its inner side disappears 

 in the form of rays towards the base, in such a way that often only a third or a 

 fifth of the expanse of the forewing remains for the very dark bright blue. This 

 gives to the butterfly a very special facies. Specimens which approach those of 



