336 Mr. G. A. K. Marshall on the Genus Byblia. 



Col. Swinhoe was evidently unable to distinguish one from 

 the other, and therefore his evidence as to the occurrence of 

 the dry-season form at all times of the year can hardly be 

 considered of any weight. Therefore in Africa : — 



Wet-season form. Dry-season form. 



B. ilithyia, Drury = (Unnamed). 



{B. ilithyia, Y&r. vulgaris, Stand.) = B. ilithyia, var. achelo'ia, Wallgr. 



And in India : — 



Wet-season form. Dry-season form. 



B. ilithyia, Drury = {B. simjylex, ButL). 



The recognition of the seasonal forms of this species in 

 South Africa has hitherto been based only on observations in 

 the field ; but I am now glad to record that my friend 

 Mr. J. M. Hutchinson, of Natal, has lately succeeded in 

 proving it by breeding experiments. While staying with 

 him in February of this year we obtained a number of eggs 

 laid by the wet form of ilithyia, which emerged in the end 

 of March and beginning of April as the same form. Mr. Hut- 

 chinson then secured eggs from this latter brood and succeeded 

 in getting fourteen of them as far as the pupa stage, though 

 many of the larvffi were stunted owing to tiie great difficulty 

 of finding food for them on the parched veldt. As a result 

 of this starving only one out of the fourteen pupaj emerged 

 properly, though a number attained their full development in 

 the pupa but had not sufficient vitality to emerge. All these 

 specimens, however, exhibited in miniature the unmistakable 

 deep ferruginous white-striped colouring on the underside of 

 the hind wings characteristic of the dry-season brood. The 

 single specimen which emerged is a somewhat dwarfed female. 

 The underside is of a lighter ferruginous than usual and 

 closely resembles that part in the Indian dry form. On the 

 upperside the extraordinary reduction of all the black bands 

 gives it a very singular appearance, the broad submarginal 

 band in the hind wing being reduced to a narrow macular 

 line, and the same feature in the fore wing being almost 

 obsolete. But at the same time in the hind wing the median 

 blackish line, which is only faintly indicated in normal 

 specimens, is here strongly marked, and the enlarged marginal 

 spots of ground-colour are each clouded centrally with a 

 fuscous patch, which is large and distinct in the three lowest, 

 but gets smaller and fainter towards costa. '; 



As a general rule the upperside black markings are almost I 

 the same in winter as in summer; but this season many , 



