( Ixxxix ) 



distorteJ, being covered on the npperside by a fold i)rojecting backwards from 

 the subcostal vein and ending beyond the apex of the cell between li' and R'-. 

 The width of the fold is different in the three species, being greatest in Epistor 

 t/oryon. Underneath the fold— /.«. covered by it — there is a mass of rather large, 

 short, broad, uon-dentate, creamy white scales and a bundle of woolly scale-hairs. 

 The distortion of tlie cell and the neuration is best visible on the underside of 

 the wing, where the cell bears short scaling, contrasting with tiie more woolly 

 scaling on the rest of the wing. In the c? of Eijistor carifer there is, besides, 

 aiiotlier strnctnre on the forewing, cjnsistiug of an oblong and rather large 

 cavity on the npperside in the cell near the base. The cavity bears erect 

 scale-hairs ; the wing bulges out on the under surface, and is here covered with 

 short anl broad scales. All three species have a very woolly abdomen in the 

 male sex, the hair-scales, wliich are long subdorsally, being directed obliquely 

 dorsad (exce[»t on the first tergites) and massed together in flakes. Tiie 

 hindlegs, inclusive of the tarsi, are also very woolly in tbese males, appearing 

 compressed and broadened. Such sexual distinction in the legs like this occurs 

 also elsewhere, tiie forelegs oi Chromis erotus, the hindlegs oi F/tolas anc/temolus, 

 and the hindtibia of Hiinnntoirles undata, for instance, being broadly scaled in 

 the males and simple in the females. 



The sexual differences in the antennae have been noted above. Rhopalo- 

 psyrlte is the tiuly instance where the antennae are the same in the two sexes. 

 The palpi are on the whole smaller in the female than in the male ; the most 

 obvious differences occur in the Ambali'^in'n'. The tongue is not rarely shorter 

 in tlie female than in the male (I'rotambuli/x, for instance). The abdominal 

 end-tufts are also very often different in the sexes, tlie female possessing in such 

 cases the more simplified tuft or nj tut't at all (J'J//istor ; Spkecodina ; Cijpa ; 

 Uiloplionotn : etc.). The abdominal side-tufts of Oxynmhidyx are present only 

 in the males. The sjiurs of the mid- and hiudtibiae and the tibiae themselves 

 are occasionally longer in the male than in the female (some Polyptychus), while 

 the hindtarsus is longer in tlie ? than in tiie cJ of Pachylia Ji'^uti and Pliolas 

 aiichemolas ; and the armament of the tarsi is also not always the same in tlie 

 sexes, the peculiar protarsal comb found in ('ucytins being a male character 

 (PI. LXIV. f. «). The sensory hairs at the end of the fifth protarsal segment 

 (ventral side) are on the whole better developed in the female (PI. LXIV. 

 f. 1:5, s). 



The wings, whicli are generally more elongate in the male, show very con- 

 sjiiciious dimorphism in some instances : Poh/pfi/rln(s pauperculu and ruiitraria ; 

 the species of Siaeriiithidux ami Deyma.ptcnt : Oryhu. achemenides ; Ejdntor. 



More frequent than conspicuous difiereiice in shape is dichromatism. The 

 sexual difference in pattern and colour is often so striking that the sexes have 

 lieen mistaken for distinct sjiecies. Such obvious differences are observed in 

 Epistor, Jlimintoides, Oiyba achemenidea, Vnendosphinx, IsnynnfltuSy Krinnyis, 

 Coelo/ua /'/drh/otutd, Ilerse roiico/ndi (not cinyidnta), Mitumimus (instrulasiae, 

 and other species. 



