288 
SOUTH-AFRICAN BUTTERFLIES. 
Pyrgus Diomus, MoschL, Yerh. Zool. Bot. Gesellsch. Wien, 1883 p 
286. 
Hesj)eria Sandaster, Staud., Exot. Schmett, ii. pi. 100 (i888).i 
Exp. al., I in. — I in. 2 lin. 
Aspect of F. Vindex, Cram., hut not of so deep a Mack, with the 
spots of a duller white and mostly rather narroiver ; cilia yellowish- 
white, loith the Uack interruptions duller and not so sharply defined. 
Fore-wing : basi-costal whitish more diffused, not forming a distinct 
white mark inwardly ; cellular spots narrower, the inner one occa- 
sionally wanting ; in discal row there is no separate fourth spot, that 
marking heing immediately and vertically heneath, and completely united 
with third spot. Hind-iving : basi-cellular spot usually small and 
indistinct, and sometimes wanting; median band narrower, duller, 
and more oblique than in Vindex, crossed rather conspicuously by end 
of black median nervure and origins of its second and third nervules, 
and often narrowly and indistinctly prolonged towards costa. Under 
SIDE. — Hind-wing and apical area of fore-wing pale greyish or yellowish- 
ochreous, usually ivith a slight greenish tinge in $ ; hind-wijig with sub- 
hasal and median ivhite stripes very oUique^ well separated — the former 
rather vaguely defined internally and inferiorly, — the latter with well- 
defined edges (not much denticulated), continuous, and varying little 
in width from costa to where it joins anal-angular white ; white spots 
of siibmarginal row confluent into an irregularly-denticulate rather ill- 
defined streak, also ohliquely placed and running almost parallel with 
median hand ; beyond this streak, the hind-marginal border is much 
paler than the rest of the ground, and often nearly white in $. Cilia 
beneath rather indistinctly interrupted with greyish-ochreous, espe- 
cially in hind-wing. 
A fine $ example taken in Basutoland by Colonel Bowker varies 
in possessing much enlarged discal spots in the fore-wings. 
This species is readily recognised by the peculiarly oblique white 
bands on the under side of the hind-wings ; and Herr Moschler Qoc. 
cit.) was undoubtedly right in dissenting from my suggestion in 1866 
that it was probably a variety of Vindex ; but I had as long ago as 
1870 {Trans. Ent. Soc. Lond., p. 385) corrected that suggestion, and 
stated that I had seen reason to hold Diomus as distinct. 
About Cape Town this butterfly is numerous ; its habits are precisely those 
of P. Vindex, and the two forms fly in company. Though having an exten- 
sive range in the Southern Tropical Region, Diomus does not appear to have 
been recorded from any locality north of the Equator. Its distribution in 
South Africa proper seems to be general, but it has appeared more rarely than 
Vindex in collections received. 
^ Dr. Staudinger's figure has no resemblance to P. Sandaster, Trim, (see below, p. 291), 
but represents an apparent 9 of P. Diomus. 
