PLEEEIUS. 89 



The male is of a deep violet-blue, with rat^her broad brown 

 borders, and white fringes. The female is brown, more or 

 less blue at the base, and with a row of sub-marginal black 

 spots, surmounted with orange, on the hind-wings. The 

 under side is grey in the female, but tinged with blue, especi- 

 ally at the base, in the male. They are marked with numerous 

 ocellated spots, and on the hind-margin of the hind-wings is 

 an interrupted orange-tawny band, containing six bright silvery- 

 blue spots, crowned with a series of black crescents. 



The larva is dull green, with the head and legs blackish, a 

 ferruginous line along the back, and oblique ones of the same 

 colour, bordered with white, on the sides. It feeds on broom, 



Upper side of female. 



sainfoin, and various kinds of trefoil and vetch. There are 

 two broods in the year, as in most of the small " Blues," 

 the Butterflies appearing from May to August. The pupa 

 is dull green. 



There is a closely-allied species, P. argyrognomoji (Berg- 

 strasser), to which the Linnean name of argus is applied by 

 many authors, It is common on the Continent, but of doubt- 

 ful occurrence in England, and may be distinguished from our 

 Silver-Studded Blue by having only a very narrow black border 

 m the male. Both species are very variable on the Continent, 

 or else there are several closely-allied and ill-differentiated 

 species. The British form of P. argus does not appear to 

 vary. 



