502 Dr. A. G. Butler A Revision 



T. acoste represents the wet-season phase, T. halimede the 

 intermediate, and T. ccelestis the dry-season phase of the 

 species ; but they are none of them confined to seasons, but 

 occur (as is the case with other species in very arid countries) 

 as mere coexistent variations. If the species could be trans- 

 ferred to a variable climate, doubtless the varieties would 

 become strictly seasonal forms, as is the case with other 

 species of Teracolus. Our series of this species is very fine. 



84. Teracolas venosus. 



(5 1 . Idmuis venoea, Staudinger, Exot. Schmett. p. 43, pi. xxiii. (1.885) ; 

 $ , Holland, Proc. U.S. Nat. Mus. vol. xviii. p. 759 (1896). 



Mombasa. 



This is a wet-season form somewhat resembling T. acaste, 

 but entirely without the orange flush on the upper surface of 

 the wings. It would not surprise me to find that in the dry 

 season the male had a tint of orange and that the female 

 resembled a washed-out T. ccetestis. However, this is mere 

 conjecture. Mr. Marshall says that T. venosus comes closest 

 to the halimede group. I would go a step further and say 

 that it belongs to that group, for it differs in nothing but the 

 absence of orange colouring. 



85. Teracolus heliocaustus. 

 Teracolus heliocaustus, Butler, P. Z. S. 1885, p. 768, pi. xlvii. figs. 8, 9. 



Somaliland. 



Intermediate between T. halimede and T. pleione, being a 

 little nearer to the latter, which it represents on the Somali 

 coast. It is a dry-season form, varying much in the black 

 markings of the upper surface. 



8G. Teracolus pleione. 



Pontia pleione, King, Symb. Plays., Ins. pi. viii. figs. 7, 8 (1829). 

 Idmais miriam, Felder, Reise der Nov., Lep. ii. p. 190, pi. xxvii. 



figs. 3, 4 (1865). 



Teracolus chrysomdis, Butler, Cist. Ent. i. p. 244 (1874). 

 Idmais eucJieria, Mabille, Bull. Soc. Ent. Fr. (5) ix. p. clxxiv (1879) ; 



Grand. Madag. pi. xi. fig. 5 (1887). 



"White Nile and Arabia. 



T. miriam ( = chrysomelis) is the dry-season phase of 

 T. pleione ; but in Arabia both forms occur as mere varieties 

 simultaneously and emerge on the same day from the same 

 batch of pupa). It would be interesting to know whether the 

 forms are seasonally constant on the White Nile. 



