184 BKITISH BUTTERFLIES. 



underside is more strongly developed in the $ s than in the $ s. It is 

 particularly brilliant in some of the continental races. It consists, in 

 its simplest form, of a series of orange lunules surrounding inwardly 

 the series of black marginal dots, and being in turn edged inwardly 

 by a series of fine black lunules, but usually the orange lunules are 

 united into a very distinct, transverse, subterminal band ; this is 

 followed by a transverse band of white, also, in its simplest form, 

 consisting of a series of disunited lunules, but sometimes well- 

 developed into a definite white band, more frequently on the hind- 

 wings than on the forewings. In some races it is very conspicuous. 

 The Bosnian $ s are particularly noticeable for their larger spots on 

 the underside, and white submedian band on the hindwings, one 2 in 

 the Brit. Mus. coll., has the white band well-developed on the fore- 

 wings also. The various described forms of this species are as follows: 



Underside aberrations. 



a. ah. vulgaris, Meyer-Dur, " Schmett. Scbweiz," p. 67 (1851). — Alis subtus 

 laetius cinereo-griseis, ocellis grandis. Switzerland (Meyer-Diir). 



Wheeler notes that this presumably means "alis subtus latius 

 cinereo-griseis, ocellis grandibus." Meyer-Dur seems to describe this 

 in contradistinction to the next, possibly as the "meadow," as against 

 the " heath " form, the latter being usually browner in its underside 

 coloration than the former, but all the former are not large-spotted, 

 nor all the latter small-spotted, whilst the lowland Valaisian specimens 

 are often pale grey-blue in their ground-colour. It might even be 

 compared in its underside characters, with alcippe, Stphs. 



/3. ab. valesiana, Meyer-Diir, " Scbmett. Schweiz," p. 67 (1851). — Alis subtus 

 fulvogriseis ocellis minutis. Switzerland (Meyer-Diir). 



The " heath " form specimens, in certain sandy districts, are 

 exceptionally brownish in the tint of the underside ; the darkest we 

 know come from Fontainebleau Forest, where, also, P. argyrognomon 

 has an exceptionally brown underside in the $ s as well as the ? s. 



y. ab. unipuncta, Mousley, " Ent. Rec.," xiv., p. 341(1002); Leonh., " Ent. 

 Zeits. Guben," xviii., p. 53(1001). — For the rare form of Plebeian aegon with a 

 basal spot to the underside of the forewings, I propose the varietal name ab. 

 unipuncta. The specimen happens to be a ? of the ab. (et var.) eorxica form, and 

 was taken by myself at Witherslack, in July, 1001. In addition to the already- 

 mentioned variation, the black spots on all the four wings are large, and well- 

 developed, including the metallic ones on the hindwings. The form with the one 

 basal spot is found in Polyommatua corydon, P. bellargus, and P. icarua (ab. iphiu), 

 but I have never come across it, or heard of its occurring, in either Polyommatus 

 aetrarche or Plebeiua aegon, until I captured the above specimen (Mousley). 



Leonhardt notes [Ent. Xrits. Guben, xviii., p. 53) that he captured 

 a ? of this form on July 14th, 1904, near Bern an, Brandenburg. 



5. ab. caeca, Grand, "Int. Ent. Zeits. r,iib.," ii., p. 71 (1008).-?. On the 

 underside all the ocellated spots, except two small eyes on the right hindwing. are 

 wanting; the discoidal spots arc weakly indicated, and the brown colouring is, 

 especially in the middle of the wing, traversed by white rays ((Jrund). 



Blachier notes (in litt.) a $ taken at Digne, with only the discoidal 

 lunules and the submarginal chevrons surmounted by orange colour, 

 all the ocellated spots of the submedian rows having disappeared 

 ( = ext,rc»ia). 



c. ab. marttimua, Stphs., "Cat.," 1st ed., pt. ii., p. 25 (1829); Dale, "Hist. 

 Brit. Butte.," p. 70 (1800); Walk., " Ent Mo. Mag.,"' xliii., p. 133 (1907). Argue, 

 var. 7, Stphs., " lllus. llaust.," i.. p. 01 (1828). Argue y, maritimua, Haw. 



