TERACOLUS. 87 



" The development of these larvae was very rapid, the larval stage occupying only 

 twelve days in two instances, and thirteen in the third ; the pupal stage in all cases 

 occupied eight days, thus making twenty-three days from the laying of the egg 

 to the emergence of the perfect insect. Two of the specimens emerged on 

 November 19th, and the third on the 20th, all of them being undoubted males of 

 T. auxo, Lucas ; thus definitely proving that T. fopha is only a seasonal form of that 

 species. It is perhaps worth noting that, although the larvse were reared under 

 precisely similar conditions, the imagos differed somewhat in the development of the 

 black markings on the upper side. The two earlier specimens had the hind-marginal 

 border in the fore-wings comparatively narrow, and had no sign of black along the inner 

 edge of apical patch. This is the early ' wet-season ' form. The third example, how- 

 ever, had the border slightly broader and more thickened towards the posterior angle, 

 and also exhibited a trace of black scaling along the inner edge of the patch, thus 

 showing an approach to the more heavily marked full ' wet-season ' form. Although I 

 am of opinion that the augmentation of the upperside black markings in Teracolus is 

 probably due directly to climatic causes — as opposed to the protective action of natural 

 selection, which has probably influenced the underside coloration — yet in this par- 

 ticular instance the cause of the difference in the specimens is by no means apparent, 

 as they were reared under absolutely identical conditions, and I certainly hesitate to 

 attribute it to the fact that one of them was a day longer in the larval stage." 



EXPLANATION OF THE FIGURES OF T. avn-o. 



Pl.ate i>7, fig. 1. <J Natal (J/«s. ^o«fcf/f/W). 



„ la. Underside of fig. 1. 



,, lb. $ Weenen, Natal (J/«s. Rothschild). 



„ Ic. Underside of fig. lb. 



„ Id. 9 Natal {Godmun-Sahin Coll. ; Mvs. Brit.). 



„ le. Underside of fig. Id. 



„ If. 3 Natal {£. C. BvMon; Mus. lirit.). 



„ Ig. 9 Natal (J/((.s. llothschild). 



„ Ih. c? Weenen, Natal (J/»a'. HotJischild). 



„ li. Underside of fig. Ih. 



„ Ij. ? Natal {Mils. Rothschild). 



„ Ik. Underside of fig. Ij. 



11. 9 Natal {Mus. Rothschild). 



„ Ini. Undersideoffig.il, 



