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



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



Terias irregularis, Moore, t. c. pi. xii. %. 3. 



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



Terias asphodelus, Butler, P. Z. S. 1883, p. 151, 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, ]A. v. fig. 2. 



Terias contuhernalis, Moore, Journ. Linn. Soc, Zool, xxi. p. 16 (1886). 

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

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

 Terias A^idersonii, Moore, t. c. p. 47, pi. iv. fig. 8. 



India and Ceylon, Burma, and southward to Malacca, 

 including the Mergui Archipelago. 



This species well liears 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 Terias^ and consequently hag 

 received numerous distinctive names. As every gradation of 

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

 to the nariow-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 peifcct 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 in 

 which tlie border is reduced to its narrowest limit. 



Var. 1. 

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

 mediate form is unnamed ; T. simulata is the dry-season form, 

 from which T. contuhernalis is practically inseparable. 



Var. 2. 

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

 is unnamed ; T. excavata is tlie dry-season form, from which 

 T. A ndersonii is inseparable. 



Var. 3. 



The wet and intermediate forms are both unnamed ; T. fra- 

 terna is the dry form. 



Var. 4. 



Tlie wet and intermediate forms are botli unnamed ; 

 T. purreea— patruelis is the dry form. 



