70 Dr. A. G. Butler on the Old-World 



Terias excavata, Moore, P. Z. S. 1882, p. 252. 



Terias irreffularis, Moore, t. c. pi. xii. fig. 3. 



Terias apicalis, Moore, t. c. p. 253, pi. xii. fig. 2. 



Terias asphodelus, Butler, P. Z. S. 1883, p. 161, pi. xxiv. fig. 13. 



Terias narcissus, Butler, /. c. 



Terias Swinhoei. Butler, Ann. & Mag. Nat. Hist. ser. 5, vol. xvii. p. 216 



(1886). 



Terias simplex, Butler, t. c. p. 217, pi. v. fig. 2, 



Terias contubernalis, Moore, Journ. Linn. Soc., Zool. xxi. p. 46 (1886). 

 Terias patruelis, Moore, t. c. pi, iv. fig. 5. 

 Terias fraterna, Moore, t. c. pi. iv. fig. 6. 

 Terias Andersonii, Moore, t. c. p. 47, pi. iv. fig. 8. 



India and Ceylon, Burma, and southward to Malacca, 

 including the Mergui Archipelago. 



This species well bears out Darwin's statement that common 

 and widely distributed species vary most. T. suava (com- 

 monly confounded with the broader-winged and far less 

 variable T. hecabe of S. China) exhibits more inconstancy 

 than any other species of TeriaSj and consequently has 

 received numerous distinctive names. As every gradation of 

 upper-surface pattern, from the typical broad-bordered T. suava 

 to the narrow-bordered T. narcissus, is represented at all 

 seasons, it would seem to a superficial observer that many 

 species were represented by the forms of this butterfly ; when, 

 however, it is found that these forms are not limited to locality 

 and comprise a perfect transitional series, it becomes evident 

 that they represent one extremely variable species. 



In order to facilitate their identification I shall consider 

 these intergrades as separate varieties, beginning with the 

 most broadly bordered typical form and ending with those ii 

 which the border is reduced to its narrowest limit. 



Var. 1. 



T. suava = hecabeoides is the wet-season form, the inter- 

 mediate form is unnamed T. simulata is the dry-season form 3 

 from which T. contubernalis is practically inseparable. 



Var. 2. 



T. merguiana is the wet-season form, the intermediate forr 

 is unnamed ; T. excavata is the dry-season form, from whic] 

 T. Andersonii is inseparable. 



Var. 3. 



The wet and intermediate forms are both unnamed ; T. 

 terna is the dry form. 



Var. 4. 



The wet and intermediate forms are both unnamed 

 T. purreea^patruelis is the dry form. 



