PLEBEIUS ARGUS. 181 



2. — Fuscous, with orange lunules on hindwings = ab. posterocroceus, n. ab. 



2a. — Fuscous, with orange lunules on all wings = ab. croeeolunulatus, n. ab. 



2b. — As in 2, but scaled'withblue = ab. croceopostcaerulescens, n. ab. 



2c. — As in 2a, but scaled with blue = ab. croceocaerulescens, n. ab. 



3. — Fuscous, with orange band on hindwings = ab. croccosemivirgatus, n. ab. 



3a. — Fuscous, with orange band on all wings = ab. croceovirgatus, n. ab. 



36. — As in 3, but scaled with blue = ab. croceosemivirgabus-caerulescens, n. ab. 



3c. — As in 3a, but scaled with blue = ab. croeeovlrgatus-caerulescens, n. ab. 



4-4e. — As in 2-2c, but with yellow instead of orange f substitute flavus for 



5-5c.--As in 3-3c, but with yellow instead of orange [croceus throughout. 



The whole series might be gone through again to satisfy the darker, 

 almost blackish, race, substituting nigrescent, for fuscus, as there are two 

 very distinct shades of ground colour in this sex ; in addition, almost 

 all tbe above forms occasionally have a white external edging to the 

 marginal spots — albomarginatus, or even a blue edging — caeruleo- 

 marginatus (the argyra, Bergstr., is a special form of this), whilst 

 yet again there are two \evj distinct shades of blue with which 

 the $ s are scaled (1) bright (but somewhat pale) blue = caerulescens % 

 (2) a deeper, more violet-blue = ab. violascens, and these again, 

 are applicable to all the blue forms described above. The shading 

 of the upperside of the 2 with blue scales is very interesting, 

 and produces some very remarkable and pretty aberrations. The 

 hindwings appear to be most susceptible to this form of aberration, 

 but it extends frequently also to the fore wings. In some cases this is 

 racial, as in our British moorland form, var. masseyi, and in var. 

 Corsica; in others it is quite aberrational, but, in all cases, the arrange- 

 ment of the blue scales appears to follow similar lines, beginning with 

 thinly-scaled, wedge-shaped, interneural areas, the bases of the wedges 

 on the fulvous marginal lunules of the hindwing, the apices at the 

 disc, a similar thin scaling extending from the base towards the disc, 

 the disc and costa being at first freest from blue scales, but the area 

 extending until the whole wing is covered, except the margin and 

 costa ; in the forewing a similar, but much less marked development 

 takes place, the disc remaining clear usually long after the hindwing 

 is quite covered with blue scales. Oberthiir states that, in England, 

 the 2 has often traces of blue on the deep brown ground colour of 

 the wings, and that an analogous variety occurs in the Forest of 

 Quimperle ; in the neighbourhood of Rennes the $> appears to be 

 constantly brown, without any scattered blue scales ; the form from 

 near Paris, seems to resemble closely that from Rennes. Nolcken 

 states (Lep. Fn. EstL, p. 54) that, in the Baltic Provinces, the $ often 

 has traces of blue on the upperside. One of the most remarkable 

 aberrations is that described later as duplex, Ckll., which has all the 

 superficial appearance of a gynandromorph, although composed really 

 of two halves, each representing an entirely different form of the $ , 

 one side being entirely brown, the other strongly shaded with blue. 

 Blachier notes a $ from Digne, taken June 24th, 1907, and another 

 from Uzes, June 11th, 1907, powdered with a bright violet-blue, the 

 forewings of which have the base and the middle of the wing of this 

 colour, the hindwings the lower half blue as far as the fulvous 

 lunules. The specimen captured June 20th, 1902, by Leonbardt near 

 Hiiningen,in Upper Alsace, and described as a gynandromorph (Schultz, 

 Berl. Ent. Zeits., xlix., p. 81), is merely a blue $? (see Gillmer, Soc. 

 Ent., xx., p. 131). The St. Petersburg ? s show good orange arches 



