LYCAENID. CASTALIUS. 197 
759. Castalius rosimon, Fabricius, 
Papilio rosimon, Fabricius, Syst. Ent., p. 523, n. 341 (1775) ; idem, id., Sp. Ins., vol. ii, p. 121, m. s4t 
(178r) ; idem, id., Mant. Ins., vol. ii, p. 71, n. 672 (1787); id., Herbst, Pap., pl. cclxxxix, figs. s—7 (1800) ; 
Hesperia rosimon, Fabricius, Ent, Syst., vol. iii, pt. 1, p. 288, n. 104 (1793); Polyommatus rosimon, Godart, 
Enc. Méth., vol. ix, p. 658, n. 141 (1823) ; Lycena rosimon, Horsfield, Cat. Lep. E. 1. C., p. 71, n. 6 (1828) ; 
id., Snellen, ‘Tijd. voor Ent., vol. xix, p. 152, n. 41 (1876) ; Cupido rosimon, Druce, Proc. Zool. Soc. Lond., 
1874, p. 106, n. 1; id., Snellen, Tijd. voor Ent., vol. xxi, p. 17, n. 79 (1878); Lamfpides rosimon, Wood-Mason 
and de Nicéville, Journ. A. S. B., vol. 1, pt. 2, p. 235, n. 41 (1881) 3 Castalius rosimon, Hiibner, Verz. bek. 
Schmett., p. 70, n. 697 (1816) ; id., Butler, Cat. Fab. Lep. B. M., p. 162, n, 1 (1869); id., Moore, Lep. Cey., 
vol. i, p. 83, pl. xxxvi, fig. 2 (1881) ; id., Distant, Rhop. Malay., p. 215,n. 1, pl. xxii, fig. 20, female (1884) ; 
Papilio maimon, Fabricius, Syst. Ent., p. 534, mn. 395 (1775); idem, id., Sp. Ins., vol. ii, Pp. 137, n. 635 
(1781) ; idem, id., Mant. Ins., vol. ii, p. go, m. 817 (1787); Hesperia maimon, id., Ent Syst., vol. iii, pt. 
1, P. 349, n. 327 (1793) ; Papilio clyton, Cramer, Pap. Ex., vol. i, pl. Ixvii, figs. F, G (1775); Castalius 
clyton, Hilbner, Verz, bek, Schmett., p. 70, n. 695 (1816) ; Polyommatus clyton, Godart, Enc. Méth., vol, ix, p. 
679, n. 193 (1823) ; Papilio coridon, Cramer, Pap. Ex., vol. iv, pl. cccxl, figs. C—E (1781); Castalius NAXUS, 
Hiibner, Verz. bek. Schmett., p. 70, n. 696 (1816); Castalius chota, Swinhoe, Proc. Zool. Soc. Lond., 
1885, p. 133, n. 68; C. approximatus, Butler, Ann, and Mag. of Nat. Hist., fifth series, vol. xviii, p. 186, 
fn. 27 (1886). 
Hapitat : Throughout India, except the desert tracts ; the lower Himalayas, Ceylon, the 
Andaman and Nicobar Isles, Assam, Burma, Malay Peninsula, Siam, Java, Celebes, Timor, 
EXPANSE: &, 2, ‘9 to 14 inches. 
DESCRIPTION : ‘* MALE. UPPERSIDE, doth wings white, with a grayish-blue base, over 
which a brilliant silvery irroration, varying according to the light, is thinly spread ; anterior 
margin of both wings blackish-brown, a border of the same colour passing along the posterior 
margins, broader on the hindwing, indented at the inner edge, and bearing a regular series of 
white rings formed by crescents applied to each other, the exterior being in many cases so 
obscure, that merely a series of lunules directed outwards is apparent: a very irregular series 
of square or oblong maculze passes along the inner edge of the marginal border, and several 
maculz, more elongated, are scattered over the disc and along the anterior margin of both 
wings. UNDERSIDE, doth wings white. Forewing, an oblique band of black extends from the 
base to the anterior margin, the interrupted macular fascia and the transverse marks of the 
disc and anterior margins appear more prominently on the underside ; and parallel with the 
posterior margin extend three rows of small oblong spots, of which three, in the posterior 
series near the anal angle of the hindwing, are covered with a bluish-silvery irroration, Aad, 
body, and abdomen, black above and white underneath, the latter banded at the sides ; antenne 
with white annuli. FEMALE, larger than the male. UPPERSIDE, doth wings with the posterior 
border broader, the black colour more intense.” UNDERSIDE, doth wings as inthe male, 
( Horsfield, 1. ¢.) 
C. rosimon, like many other butterflies of this family, is subject to considerable seasonal 
dimorphism, specimens which are on the wing during the rains being much darker and more 
heavily marked than those occurring in the dry-season. Two of these dry-season forms have 
lately been described as distinct species as below.* It is probable that all localities which have 
two strongly-marked seasons, a wet and a dry, produce specimens to match these descriptions. 
* Castalius chota, Swinhoe, Proc. Zool. Soc. Lond., 1885, p. 133, n. 68.. Hasirat: Poona, February, 
May. ExpansE: ‘7 to’g ofan inch. DescripTion: ‘ Smaller than typical C, vosz#zon, Fabricius. MALr and 
FEMALE. UPPERSIDE, 60th wings with the marginal bands narrow, and the discal spots smaller. UNDERSIDE, 
both wings with the spots also much smaller.” (Szwixhoe, 1. c.) 
Castalius approximatus, Butler, Ann. and Mag. of Nat, Hist., fifth series, vol. xviii, p. 186, n. 27 
(1886). Hasrrar: Katha on the Irrawaddy, Upper Burma, January ; Bombay. ExpansE: 1°25 to 1°30 inches. 
Description: ‘ Nearest to C. chota, Swinhoe, but running larger; it differs chiefly from C. vosimon, 
Fabricius, in the narrower borders to the wings and in the absence of the last of the discal black spots 
towards the external angle of the forewing, the other five spots being well-separated; also in the absence of 
the black spot close to the border of the hindwing towards the apex, and in the indistinct and minute 
character of the marginal spots on the underside.’’ 
‘“We have a pair of this form taken in Bombay by Colonel Swinhoe. Whether it is a species or only a 
well marked variety nobody can definitely decide without breeding it ; at any rate it is as distinct as the other 
named forms of the group.’ (Butler, |. c-) 
