194 Dr. F. A. Dixey on 



is the fact that, as recorded by de Niceville himself, the 

 different forms of C. pyi'cinthc, though corresponding to the 

 seasons in some parts of its range, are independent of them 

 in others. Thus, in speaking of this species under the 

 name of C. chryscis, Drury, he notes that "it is not seasonally 

 dimorphic in Sumatra as it is in India." * Again, he 

 remarks under C. 'injTantlic, "Moore in the ' Lepidoptera 

 of Ceylon ' gives four forms of this species as separate 

 species; C. gnoma, Fabr., C. ilea, Fabr., G. chryscis, Drury, 

 as well as typical G. pyranthe. Manders notes that as far 

 as his observations go these four forms are not dependent 

 on season, but appear indiscriminately nearly throughout 

 the year, those flying in the dry season from February to 

 April being a little smaller than those found during the 

 rest of the year." f On the other hand he says, " True 

 C. pyranthe is not very common in Mussoorie in the rains ; 

 the dry-season form, G. gnoma, Fabricius, even less so. 

 In the Dun both forms are common in their respective 

 seasons." + 



If then we are to trust the observations that have been 

 cited, we are led to the conclusion that in these Catopsilias, 

 viz., G. pomona and G. pyranthe, we have to deal with two 

 polymorphic species, each of which has no doubt several 

 geographical forms, and each of which shows, in most 

 localities, a special tendency to cleavage into two well- 

 contrasted types. These latter phases in each case are in 

 some parts of the range of the species dependent on 

 seasonal changes ; in other parts, however, they show no 

 such connection. 



We may now pass on to the consideration of similar 

 irregularities as shown in other groups. 



3. Irregularities of Seasonal Dimorphism in 

 VARIOUS Genera. 



It has been recorded by most of those who have ex- 

 perimented on the subject, that there are individual 

 differences in the reaction of members of the same brood 

 to what appear to be identical conditions of the environ- 

 ment. A conspicuous instance of this is the well-known 



* Jonrn. Asiat. Soc. Beng., LXIV, 1895, ii, p. 490. 



t Ihicl, LXVIII, 1899, ii, p. 211. 



X Journ. Bombay Nat. Hist. Soc, XI, 1898, p. 586. 



