62 



THE BRITISH NATURALIST. [April 



before the fissure; costal fringes of the anterior lobe entirely dark." 

 Of var. plagiodactyla , he writes: — "9"' F.-w. greyish-brown, the inner 

 margin paler; the costa beyond the middle clouded with dark brown; 

 before the fissure is a blackish blotch and in the anterior lobe is a 

 short black streak." (" Manual," II., p. 442). Mr. Gregson whites 

 of the imago (under the name oi plagiodactylus, which he afterwards 

 altered to scabiodactylus: — "Head and face fuscous; fore wings 

 irrorated with dark scales on the anterior portion ; inner margin 

 ochreous, irrorated; a small dark spot on the third part of the wing; 

 then a large wedge-shaped one at the head of the cleft, and a dark 

 streak in the first lobe, the first cleft-edged with a whitish streak; 

 under wings, together with their cilia, brownish ; thorax dark ; first 

 segment of abdomen triangular, ochreous, edged with white ; upper 

 surface of the legs dark, spurs and feet light. I am not aware that 

 this insect or its larva have ever been previously described; the 

 specimens from which the above descriptions were made were found 

 in the larva state at Llanferris, when I was there in April last, in 

 company with Mr. Greening ; the bred specimens were of average 

 darkness, but bred specimens vary much in colour." (" Entom.," 

 Vol. III., p. 186). 



Variation — The difficulty of the synonomy of this species is to a 

 great extent connected wdth the variation in this species. There is a 

 fair amount of variation in the size of the specimens, and still 

 greater A'ariation in their colour. The prevalent colour is grey, but 

 the inner marginal area is frequently tinged with brown, and 

 sometimes the whole wing is similarly coloured, the insect frequently 

 being rather brown than grey. This was especially marked in some 

 specimens I saw in Mr. Sydney Webb's collection. The local forms 

 which thus vary have been differently named, and Mr. C. G. Barrett 

 points out that the British specimens of aridiis, plagiodactylus, Sta. and 

 scabiodactylus, Gregson are only local forms of this species. He 

 writes: — "I have been investigating plagiodactylus from time to time 

 for a dozen years, and am not fully satisfied yet. The distinctive 

 characters, as given by Mr. Stainton, are, — the dark clouding on the 

 costa, and the short black streak on the anterior lobe of the fore- wing. 

 The insect is common in chalky places among Scabiosa columbaria, 

 sometimes swarming about disused chalk pits, — from nine to ten lines 

 in expanse of wings, usually with the markings more or less distinct, 

 and sometimes very pronounced, but also frequently varying in the 

 direction of faintness of those typical markings, until, in some 

 specimens, they entirely disappear. On the other hand, we find 

 scattered all over the country, almost wherever Scabiosa succisa grows, 

 the ordinary M. bipunctidactylus, varying from eight to ten lines, the 

 smallest generally occurring in the drier localities, where the scabious 



