65 



changed his residence, and travelled with the pup^e and caterpillars 

 in the course of transformation of the summer brood of Pieris napi; 

 and although this brood of that species, under ordinary circumstances, 

 always emerges in the summer, generally in July of the same year as 

 the form napace, yet none emerged in that year. They were kept 

 during the winter in a warm room, and the first butterflies emerged 

 in January, 1873, the remainder following in February, March, and 

 April, and two females not until June ; all appeared, however, as 

 exquisite winter forms. The whole course of development was pre- 

 cisely as though cold had acted on the pupse. 



Notes on the Wet and Dry Seasons forms of certain 

 species of Rhopalocera. 



By J. Jenner Weir, F.L.S., F.E.S., etc. Read February 2^ih, 1892. 



At the last meeting of the Society I pointed out that the imagines 

 of the spring emergence of Pieris napi on the upper side are more 

 dusky, and on the under side darker than the form of that species, 

 variety napcecE, which appears in summer, and also that the latter 

 had on the upper side the blick blacker and the white whiter than 

 in the spring form ; and, further, that if the chrysalids of the latter 

 had their emergence retarded, they emerged as imagines of the true 

 P. napi, and not as the variety napcBCE. At the same time I should 

 be prepared to occasionally meet with the form napi in the summer, 

 because it is no uncommon fact, well-known to most of us, that the 

 development of lepidoptera, both in the larval and pupal state, is 

 often retarded, and sometimes accelerated, so that a rule without 

 any exception cannot be insisted on. 



I now wish to draw your attention to another class of facts, which, 

 unfortunately, I am not able to illustrate by familiar British insects 

 because our climate does not afiord the necessary conditions. In 

 the Indian region it is now placed beyond doubt that many species 

 which were looked upon as perfectly distinct are wet season and dry 

 season forms of the same insect. 



I have brought for the purpose of illustrating this very interesting 

 subject, specimens of the wet and dry seasons forms oi Junonia 

 asterie, Linn., 2ind Junonia almana, Linn., belonging to the Nympha- 

 linae. It will be seen that in asterie, the wet season form from Hong 

 Kong, the upper wings are obtuse and the lower slightly produced 

 at the anal angle, and the upper and lower wings have well-developed 

 ocelli on their under sides. In the dry season form, almana, the 

 upper wings are far more falcate, and have a highly developed angle 

 at the end of the upper radial nervure, and a lesser angle at the end 

 of the first median nervule, the lower wings have the anal angle 



