RHOPALOCERA MALAYANA. 289 



Genus DELIAS. 



Delias, Hiibner, Verz. bek. Schmett. p. 91 (IKIC)) ; liutl. Cist. Ent. vol. i. p. 40 (1870); Moore, Lcp. Ceyl. 



vol. i. p. 139 (1881). 

 Cath(Binia, Hiibu. Verz. bek. Sclimett. p. 92 (1816). 

 Pontia, Hiibii. (uec Fabr.), Verz. bek. Sclimett. p. 92 (1816). 



Thijca, Wallengr. Sveusk. Acad. Forh. 1858, p. 76 ; Wall. Trans. Knt. Soc. ser. 8, vol. iv. p. 344 (18U7). 

 Pieris, sect. 1, Doubl. Gen. Diuru. Lep. p. 44 (1847). 



Anterior wings somewhat elongate ; costal margin moderately convex, the apex rounded, outer 

 margin obliquely rounded, inner margin nearly straight. Costal nervure extending to about two-thirds 

 of wing ; first subcostal nervule emitted at about one-fourth before end of cell, second and third bifurcating 

 near apex of second, fourth springing from second at about one-third beyond end of cell ; upper disco- 

 cellular obliquely directed outwardly, lower disco-cellular somewhat concave ; discoidal nervule emitted at 

 central apex of cell ; median nervules emitted wide apart, first and second a little nearer to each other 

 than second and third. Posterior wings clougately subovate ; the costal margin oblique, the posterior 

 margin convex, abdominal margins obliquely divergent towards anal angle. Costal nervure extending 

 to about two-thirds of costal margin, first subcostal nervule emitted at about one-third before end of cell, 

 second almost midway between bases of the first and of the discoidal nervule ; upper disco-cellular oblique, 

 lower disco-cellular very slightly concave ; upper median nervule emitted at apex of cell, second and third 

 median nervules almost twice as wide apart at base as first and second ; submedian nervure slightly curved 

 outwardly ; internal nervure reaching about centre of abdominal margin. Body somewhat robust : head 

 and pronotum clothed with long hairs ; palpi porrect, extending considerably beyond the head, and clothed 

 with long hairs beneath ; legs long and slender ; antenna3 with a well-formed and moderately channelled 

 apical club. 



This is au extremely large. genus, and one in which the coloration of the wings assumes 

 a most vivid and extraordinary character. It is on the under surface of the wings that the 

 most brilliant hues and markings are found, and these are often of a bizarre and ostentatious 

 description. Mr. Wallace has thought that these butterflies may have some special protection 

 which renders the disguise of sombre colours unnecessary, and this seems the more probable 

 when it is found that some of them are the subjects of "mimicry" by species of the genus 



I'rioneris,* 



Delias has a wide geographical distribution; it inhabits Continental India and the 

 neighbouring islands, Burma, the Malay Peninsula, the length and breadth of the Malayan 



■■'■ Trans. Eut. Soc. ser. 3, vol. iv. p. 344. , ,, , • xi i . i,„;„i,( 



This exposure of the gaUy-coloured under sm-faces of the wings is olten equalled m moths where a briglit- 



oolom-ed upper surface is only seen when at rest. Protection is, however, generally afforde. ni some respect. 



Mr. Johnston observed such a case on the banks of the Congo. He saw such a moth sittnig •complacently, not_^).-aimg 



"large green mantisses or 'praying insects" are chasing small flies with their great P"""''"'- ^'f '''^'^V T . Klvlr TL^^ 

 then a blue roller-bird snaps up a mantis in spite of its wonderful assimilation to its lealy surroundings ^ /''^ ^ ; , ^^^^^^^^^ 

 p. 37). Another new feature in the theory of mimicry is afforded by that compet. nt t;-"^^^'! ;"« '"f "'"" 't\,W ..^ts w i ch thev 

 In Brazil he noticed spiders which mimic ants, but the peculiarity was that the spiders " ^''^ ''« 1 '"''^'"^ ^^ ' "'^^^.^^^^^^^^^ 

 mimic." But, as Mr. Smith remarks, " It is difficult to suppose that the ,iU,ck-wiUc.a ants would be '^'^^"; «^' '^^'^;^i^,,r;„t"/* 

 a resemblance ; and in any case it would seem that the spiders do not require such a disguise o 7^^P'";%;^2;X s uc,mn« 

 The supposition is therefore hazarded that as ants enjoy an immunity trom the attacks ol birds, the sp.deis thus ucquuo 

 a similar protection from the same enemies" (' Brazil, the Amazons., and the toast, p. ^^<i). 



Mabch 20, 1885. ^ ^ 



