100 MR. C. N. BARKER ON 



patterns o£ their representatives in countries with well-defined 

 seasons. 



Wet season forms are equally foreign to desert countries 

 such as Sind in western India and other reo-ions of a similar 



o 



physical character. 



Nevertheless there are a good many exceptions to these 

 general rules. In N.E. Sumatra, Dr. L. Martins, an 

 experienced entomologist and observer, records the fact that 

 Catopsilia crocale,C?'.,and its dry season phaseC. pomona, 

 L., both occur together and quite independently of the time 

 of the year, Melanitis leda, Z., in botli its wet and dry 

 forms, is also resident in the island. At Karachi, vvliich is a 

 sea-port on the fringe of Sind, we have the assurance of 

 Col. Swinhoe that he has taken all the seasonal forms of 

 certain Eastern Teracoli and that he has also captured 

 Byblia simplex, Butler, the supposed dry season form in 

 India of B. ilithyia, Drury, practically all the year round. 

 Again, in Aden Ool. Yerbury correctly states that the wet, 

 intermediate, and dry phases of Teracolus eupompe, 

 T. evagore, etc., all occur^ but that no seasonal significance 

 can be attached to their occurrence as they co-exist. Terias, 

 as Butler notes, like Teracolus, in very arid countries 

 produces three phases of a species as co-existent varieties. 

 Dr. Dixey sums up these irregularities as follows : — 



'^ Statements of this kind, the list of which could be 

 largely extended, go far to show that the case of Catopsilia 

 pomona and C. crocale is by no means an isolated one and 

 that just as there are regions in which more than one 

 geographical form of a widely-ranging species may be found 

 flying together, so there are districts of a greater or smaller 

 extent where diverse forms of a species, confined for part of 

 its range to definite seasons, may all occur simultaneously. 

 No doubt the data are as yet ipsufficient for a complete 

 explanation of these phenomena. It seems, however, clear 

 that the forms or phases which are usually called ' seasonal ' 

 may occur under many diverse conditions and in many 

 different proportions. It appears further that they do not 

 fall into a regular system of succession, except in the 



