94 LEPIDOPTERA INDICA. 



posterior margin convex ; sexual mark between lower median and submedian yein 

 Jong, broad, and conspicuous, clothed with well- separated narrow tapering scales 

 with either bidentate or tridentate tips, and a few intervening slender pointed scales. 

 On the underside of the wing the sexual streak is clothed with minute round-tipt 

 scales, innumerable longer slender claviform and thread-like scales bristling all over 

 the surface. Hindioing broad, apex and posterior angle convex, exterior margin 

 oblique. Palpi short, thick, laxly hirsute, tip pointed. 



Type. — P. Alcathoe. 



From typical Crastia the males of this genus differ in having a conspicuously less 

 triangular form of f orewing, which is also broader, and either glossed with purple- 

 violet or deep-blue, and in possessing a much longer and broader sexual streak. 



PENOA ALCATHOE (Plate 31, fig. 1, la, b, c, <? ? ). 



Danais Alcathoe, Godart, Encycl. Meth. ix. p. 178 (1819). 



Euplcea Alcathoe, Butler, Journ. Linn. Soc. Zool. xiv. p. 301 (1878). Marshall and De Niceville, 



Butt, of India, i. p. 86, pi. 9, fig. 17, ^ ? (1882). 

 Penoa Alcathoe, Moore, Proc. Zool. Soo. Lond. 1883, p. 274 ; id. Journ. Linn. Soc. Zool. 1886, p. 31. 

 Eui^laia Douhledayi, Felder, Eeise Novara, Lap. ii. p. 337 (1867). 



Imago. — Male. Upperside dark purplish violet-brown. Cilia white spotted. 

 Foreiving with violet-blue reflections in certain lights, and occasionally the lower 

 marginal spots oE the underside slightly visible; a straight elongated rather broad 

 sexual mark between the lower median and submedian vein, clotlied with well- 

 separated narrow tapering scales, either with bidentate or tridentate tips, and a few 

 intervening slender pointed scales. Hindwing paler, and of a more rufescent-brown 

 exteriorly ; the costal border glossy brownish-cinereous, the upper discoidal area 

 blackish, and clothed wdth narrow round-pointed scales, numerous very slender 

 slightly clavate and a few thread-like scales ; with a submarginal row of elongated 

 brownish-white anteriorly decreasing spots, disposed in pairs between the veins, and 

 a marginal row of small spots, the basal two or three spots of both rows being con- 

 fluent. Underside paler, purpurescent olivaceous -brown. Forewing with a bluish- 

 white costal spot above end of the cell, one within end of the cell, another on the 

 disc between the upper and middle median veinlets, and sometimes a short streak 

 also between the upper median and lower radial ; a large white discal spot between the 

 middle and lower median veinlets ; an elongated greyish-brown sexual streak between 

 the lower median and submedian vein, clothed with densely packed small narrow 

 round-pointed brown scales, numerous interspersed very slender claviform white long 

 scales bristling out, intermixed with a few extremely fine claviform scales, the 

 posterior border being glossy cinereous-brown. Hindwing with whitisli elongated 

 submarginal spots, and marginal spots, as on upperside, also a small bluish-white spot 



