Seasonal Dimorphisiih in Butterjlies. 207 



1897. 

 April 15. Three males and three females emerged in 

 damp tin ; one male escaped and another 

 was deformed. Three males and six 

 females also emerged in breeding-cage. 

 " On comparing the three sets of specimens the differ- 

 ences were found to be remarkably slight, all the specimens 

 being of a more or less intermediate character between 

 the wet and dry season forms (as might be expected 

 during this month for those bred under normal conditions). 

 But such slight differences as do exist appear to be fairly 

 constant. In the females the black patches on the under- 

 side of the forewings are constantly best developed in 

 those from the damp tin and least in those from the forcer. 

 Those reared under normal conditions are much nearer the 

 former in this respect, being all rather lighter, except 

 examples which are hardly separable from those reared 

 under moist conditions. The differences in the hindwings 

 are too slight to be taken into account. In the males 

 those from the forcer show a slight difference from the 

 rest in having the black mark on the underside of 

 the forewing somewhat reduced, and a greater suffusion 

 of ochreous scales on the upper side of the hindwing. The 

 others are practically inseparable. The seasonal differences 

 in this species are very clearly defined as a rule. 



" Second Experiment with Pinacopteryx pigea. 



1897. 

 April 8. Six hirvse pupated (a to/). 



„ 9. Two larvae pupated (g and h). Put a, b and c 

 into dry forcer, and d and e into damp 

 tin. 



„ 10. Two larvae (/ and li) pupated. Put g into 

 damp tin. 



„ 15. Removed a and b from forcer to breeding- 

 cage ; c was dead ; cause unknown. 



„ 16. a and b emerged; botli females. 



„ 17. / and h emerged in breeding-cage ; both 

 females. 



„ „ d emerged in damp tin ; female. 



„ 18. e emerged in damp tin ; female. 



„ „ j emerged in breeding-cage ; female. 



„ 19. g and h emerged in damp tin and breeding- 

 cage respectively : both males. 



