DERCAS. 



445 



Genus DERCAS. 



Dercas, Boisduval, in Doubleday^ Gen. Diurn. Lep. p. 70 (18i7) ; Distant, Rliop. 

 Malay, p. 308 (1885). 



" Anterior -wings subtriangiilar, the costal margin convex, the apex more or less dentate, the outer 

 margin oblique, the inner margin coucavcly sinuate. Costal nervure terminating on costa a 

 little beyond end of cell ; first subcostal nervule emitted at less than one third before end of 

 cell, second near end of cell, third and fourth subcostal nervules bifurcating nearer end of 

 cell than apex of wing, fifth emitted at about two thirds the distance between end of cell and 

 bifurcation of third and fourth ; upper discocellular nervule concave and a little less than 

 one half the length of lower, which is directed outwardly towards its base ; upper median 

 nervule convexly rounded at base and emitted from end of cell; second from a little before 

 end of cell, lower at about one third before end of cell ; cell short and broad ; submedian 

 nervure somewhat bent inwardly near base, and then outwardly along its apical half. 

 Posterior wings elongately and irregularly subovate ; costal margin obliquely convex, outer 

 margin prominently and angularly produced at upper median nervule, from whence to anal 

 angle the margin is more or less concavely sinuate. Costal nervure short, extending to about 

 half the length of costal margin ; first subcostal nervule emitted at about one fourth before 

 end of cell, second from end of cell ; upper median nervule short and oblique, lower more 

 than twice the length of upper and bent inwardly ; upper median nervule from end of cell, 

 second emitted at about half the distance from first as from third ; submedian nervure 

 moderately bent outwardly ; internal nervure bent inwardly. Body moderately robust, pro- 

 notum pilose ; antennas short, with a gradually formed but distinct apical club ; palpi short, 

 compressed, broad, and clothed with long adpressed hairs, apical joint minute. 



" This genus is of small extent, and may be taken as an Eastern representative of the genus 

 Gonepteryx. Dercas is found in Continental India, the Indo-Mulayan region, and in China. 

 One species inhabits the Malay Peninsula." {Distant, I. c.) 



Dercas wallichii. (Plate XXXV. fig. 3, c? .) 



Gonepteryx ivallichii, Doubleday, Proc. Ent. Soc. Lond. v. p. xlvii. (1848). 

 Gonepteryx urania, Butlei", Proc. Zool. Soc. Lond. 1865, p. 458, pi. xxvi. fig. 5 ? . 



" Alls omnibus lajte flavis, anticis apice acuminate nigro, macula pone medium rotundata nigra ; 



posticis rotundatis. 

 " Exp. alar. 2| unc, vel 62 millim. Habitat, India sept. 



" Head black. Antennce reddish. Thorax black, clothed thinly with yellow hairs. Anterior 

 ivincfs acuminate, falcate, the outer margin slightly sinuate below the apex, above pale bright 

 yellow, the apex marked with a black patch trisinuate internall}', the middle sinus deep, the 

 others much slighter ; the termination of the costal nervure, and also of the first and second 

 subcostal nervules, marked with a small black dot; two small black dots on the outer margin, 

 and a large rounded spot, bordered below with ferruginous, between the first and second 

 median nervules, not far from their origin. Posterior wings rounded, pale, bright yellow, 

 the terminations of the nervules marked with a small black dot. Below all the wings paler 

 than above, sprinkled with small ferruginous atoms, the discocellular nervule of both wings 

 marked with a geminate ferruginous spot, bipupilled with silver ; the anterior wings marked 



