Pierine Butterflies of the Genus Terias. 57 



with the ground-colour of the wet-season and sharply-defined 

 markings, the primaries also with an oblique row of dots, a 

 zigzag bar, or a large patch of chocolate at or near the apex — 

 this form is also often characterized bj dense dusky irro- 

 ration of the under surface. In the transition from the rainy 

 to the dry-season an intermediate form occurs. Variation, 

 in the sense of simple inconstancy of pattern, chiefly affects 

 the width of the borders on the upper surface, and, curiously 

 enough, this inconstancy in some species is dependent upon 

 season, whilst in others it occurs at all seasons. It is this 

 puzzling inconsistency in the variation of the species which 

 has been responsible for many of the synonyms in this 

 genus, as well as for much confusion in the writings of the 

 best intentioned workers respecting the geographical distri- 

 bution of some of the commoner species. 



The ]\[useum series of Old- World Terias has, for many 

 years, been the finest in existence ; and the recent donation 

 of the Godman and Salvin collection of these butterflies has 

 rendered it so complete that, in combining and rearranging 

 the two series in our cabinets, many new facts have come to 

 light and a tentative revision of the synonymy has become 

 practicable, but only breeding in every locality can finally 

 decide whether or not this reduction of the species of the 

 past goes too far or not far enough : in any case I offer it 

 to Lepidopterists as what I conscientiously believe to be a 

 step in the right direction. 



The Museum collection of typical Terias at present 

 occupies thirty cabinet drawers, nearly the whole of the 

 forms described from the Old World being represented, and 

 most of them in all their seasonal forms. It must, however, 

 be noted that, as in Teracolus^ those countries which have 

 practically no wet season nevertheless produce the three 

 phases of a species as coexistent varieties. It would there- 

 fore seem that existing variations have been adapted to the 

 seasons, and not produced by them, as has been assumed. 



Section I. 



The most simple section of the genus is characterized by 

 the absence of glandular or scale patches on the front wings 

 of the males, and includes the T. brigitta, iiise, albula, 

 agave, messalina, deva, harina, Candida, and Desjardinsii 

 groups of the genus : some of these which are only found in 

 the New World I sliall not discuss in the present paper. 



T. hrigitta group. 

 Characterized by a tolerably regular blackish border to 



