SEASONAL FORMS OF BUTTERFLIES 207 



than those of the wet, and possess paler tints. 1 In 

 attempting to understand the difference in outline which 

 is characteristic of so many butterflies in the dry season, 

 it must be borne in mind that the apex of the fore-wing 

 represents the tip and the anal angle of the hind-wing the 

 base of a leaf, and that the two are commonly joined by 

 a streak representing the mid-rib, with more or less distinct 

 lateral marks suggesting traces of the oblique veins. All 

 are peculiarly well marked in Kallima. Now the dry 

 season outline certainly cannot be explained by affinity 

 between the butterflies possessing it, inasmuch as it is 

 found independently in Satyrinae, Nymphalinae, and 

 Pierinae. Its explanation is rather to be sought for in 

 the independent protective resemblance to some feature 

 which is characteristic of the surroundings in the dry 

 season, as contrasted with the wet. Such a feature may 

 probably be found in the forms assumed by dead leaves : 

 curled and warped in the dry season, flat like damp 

 blotting-paper in the wet. 2 



The differences here described are not invariably cha- 

 racteristic of the season. Thus in Kallima paralekta, 

 of the Malay archipelago, the species rendered classical 

 by Wallace's description, the dry season appearance is 

 borne by the females, the wet by the males. The inter- 

 pretation may perhaps be found in the different habits 

 of the two sexes, or it may be an advantage to the species 

 that one set of individuals should resemble leaves of one 

 form, another set those of another form, thus increasing 

 the categories of objects in the surroundings for which 

 they might be mistaken by their enemies. 



Both seasonal forms of the Indian Kallimas tend 

 strongly towards concealment, although the individuals of 

 the dry season are probably more perfectly hidden than 

 the others. In Africa the two seasons are more sharply 

 contrasted than in India, and the differences between the 

 forms of butterflies with seasonal phases may also be far 

 greater. Some of the African species of the genus 



1 See Observations on Indian Butterflies, by T. R. Bell ; Ent. Month. 

 Mag., 1906, pp. 1 2 1-8. 



2 Proc. Ent. Soc., Lond., Oct. 21, 1903 ; see also Ent. Month. Mag., 

 1906, p. 126. 



