44 LEPIDOPTERA. 



forms. Dr. P. W. Mason lias, in his collection, a specimen 

 wholly sufi'Lifipd with dark grey. Others from the Isle of 

 Man and North Walt»s have a very slaty tinge. A curious 

 aberration in my own collection, taken by myself at Norwich, 

 has the first and second lines of the fore wings broadly 

 clouded with black-grey, the other markings being but 

 faintly perceptible. 



On the wing in June and July — on the South Coast some- 

 times at the end of ilay — and in a partial second generation 

 in August and September. 



L.\ii\A nearly one inch and a half long ; head equal in width 

 to the second segment, and having its lobes rounded ; body 

 slender cylindrical, and of almost uniform width throughout, 

 tapering very slightly indeed towards the head ; segmental 

 divisions tolerably well defined, but not overlapping each 

 other ; skin distinctly but very evenly, transversely ribbed. 

 Ct)lour of the dorsal surface and the head very pale slatv- 

 olive ; a dull olive stripe extends throughout the centre of 

 the dor.'^al an-a, and encloses within it a very fine interrupted 

 pale dorsal line ; this olive stripe however is mucli darker on 

 the last three segments than on any of the others ; there is a 

 not very well defined pale yellowish line along the subdorsal 

 area, but there are no perceptible spiracular lines ; spiracles 

 distinct, black ; ventral surface uniform!}^ very pale slate- 

 blue. (Geo. T. Porritt.) 



July till ^May, or where a second generation occurs in the 

 year, feeding up rapidly in July and the second brood of 

 larvaj from September till May or June ; on Achilka millc- 

 Julia (yarrow, milfoil), AytaaUiii vulynris (mugwort), Poten- 

 iill(( replidis (cinquefoil), and in confinement on knotgrass 

 and sallow. Rossler says Scihun alhum, SteUaria media. 

 Origanum, Tcucrium, and Ilippocrepis. 



Pupa nearly half an inch long, smooth and polished, 

 tolerably cylindrical, but attenuated toward the anal point. 

 Compared to the larva it is very stout. Ground colour of the 



