324 BRITISH BUTTERFLIES. 



their light ground colour and in the peculiarities of the latter ab. on 

 the underside. Stephens' description of his var. /3, is " wings nearly 

 immaculate above," and as he separates alcon from this, it is evident 

 that the insect here intended by him must have at least the discoidals 

 remaining, these being the last spots on the upperside to disappear. 

 Rebel (Beryes Schmett., 9fch ed., p, 75) gives parvimacula, Aign., as a 

 synonym of this form. On this point he is incorrect, as Aigner- 

 Abafi's aberration also shows much obsolescence on the underside. 

 Oberthiir is certainly in error in quoting unicolor, Horm., as a synonym 

 for this form, since the latter represents almost the extreme opposite 

 in the way of ground-colour, being so thickly sprinkled with black 

 scales as to produce a very dark appearance. 



(o) ab. poster o-immaculata, n.ab. — The hindwings on the upperside are 

 frequently without any part of the discal series of spots. 



The frequency with which this form occurs led le Chamberlain 

 (Ent., xli., p. 202) into the error of supposing it to be the typical form, 

 and consequently of naming the form in which the series, or part of it, 

 is found multo-maculata. The original description, however, after 

 speaking of black spots on the blue disc of the wings, makes no excep- 

 tion of the hindwings, necessarily implying that all the wings are alike 

 in this respect. The form in which this series of spots is absent is at 

 least as common in England as the type, and is to be found, more or 

 less commonly, in most races of this species, probably in all except 

 vars. nariina and amurensis. In the Thibetan var. tatsienluica it appears 

 to be racial in both sexes. 



(77) ab. caeruleomarginata, n.ab. — Examples in which, through obsolescence 

 of the dark margin of the hindwings, the ground colour is extended to the margin 

 of the wings. 



This aberration occurs in the lighter forms ; it is, perhaps,, 

 commoner in Cornish specimens than in those from other localities. 

 It occurs, however, in a pronounced form in some specimens of var. 

 amurensis, and appears to be racial, though not so pronounced, in var. 

 tatsienluica. 



Two $ s, captured in Cornwall in July, 1896, 1897, are noted and 

 figured (Ent., xxxiii., p. 102, pi. iii., figs. 6-7) with elongated spots on 

 the forewings so far united as to form a submedian band, the hind- 

 wings with the spots almost absent. The marginal series of spots on 

 the hindwings of normal specimens are absent, whilst the dusky 

 margins blend into the blue. The undersides are practically typical. 

 These we would call ab. caeruleomarginata-fasciata, n. ab. 



Underside Aberrations. 



(a) ab. oolitica, le Chamb., "Ent.," xli., p. 202 (19C8).— Aberration of <? and 

 ? of underside exhibiting fewer spots than the typical form, some of them 

 coalescing. Bare (le Chamberlain). 



This is one of the forms described by le Chamberlain from the 

 Cotswolds. The obsolescence of spots accompanied by the coalescence 

 of others is very rare in the Lyca?nids, though occurring in other 

 species besides arion. A somewhat analogous case is to be found in 

 those specimens of ab. conjuncta in which the marginal spots of the 

 hindwing are obsolescent or entirely obsolete. 



(/}) ab. bipuncta, Rebel, " Berges Schmett.," 9th ed., p. 75 (1909;. — Specimens 

 with two basal spots on the underside of the forewings. 



