tiESPERID.E. 269 



ance with tlie presence or absence of the coarse asliy grey 

 hairs ; also very liable to suppression, or addition, of white 

 spots, of which those in the dorsal half of the hind wings are 

 most frequently absent, and that nearest the base of the fore 

 wings less frequently so ; while it is not very unusual for the 

 two or three dots near the anal angle of the fore wings to 

 increase in size and in number, so as even at times to form a 

 complete additional row parallel with the hind margin. In 

 such cases additional pale spots, not very distinct, appear 

 near the base, the central spots are enlarged, and the fore 

 wings become altogether paler. In another form, which is 

 recurrent though rare, and of so striking an appearance as to 

 have received the varietal names of Lavaterce, Haw., Taras, 

 Meigen, the usual spots are so much elongated and enlarged 

 as to coalesce and form a broad whitish band, extending 

 across the fore wings, broadest on the costal margin, where 

 it nearly reaches the apex, but containing generally one or 

 two blotches of the ground colour. Intermediate specimens 

 occur connecting this form with the type, and every phase of 

 variation in the fore wings is faithfully followed — or exagge- 

 rated — on the underside. Curiously enough, variation in 

 the hind wings does not necessarily follow that in the fore ; 

 examples in which the latter are quite normal occur, having 

 the hind wings black except a central white spot and two or 

 three faintly whitish clouds near the margin ; and others, in 

 every gradation, from this to those which are strongly marked 

 and fully spotted. In the aberration Taras also some speci- 

 mens have the hind wings almost of a unicolorous blackish, 

 while others are fairly spotted. In a long series of gradations 

 of this vai-iety, in the cabinet of Mr. C. A. Briggs, is included 

 one specimen of which the outer half of the fore wings is 

 entirely white, giving it a most extraordinary appearance. 

 ]\lr. AVebb has a specimen, otherwise normal, in which the 

 wliite markings of the hind wings coalesce, forming a white 

 bar ; and others in which the usual spots are reduced almost 

 to dots. 



