( Hi ) 



smaller and requiring less nourishment ; this, in the author's 

 opinion, accounting for the preponderance of the male sex in 

 the dry-season flights. This periodical destruction from 

 starvation of the female larvae, and the consequent temporary 

 predominance of males, might be regarded as a provision 

 against the undue increase of the species. 



Dr. F. A. DiXBY remarked that though the results of Major 

 Manders' experiments wei"e numerically small, they were never- 

 theless of considerable interest. It appeared from the records 

 of these experiments that the emergences all took place between 

 the 5th and the 17th of December; and as the larvae were 

 collected in the same place and nearly at the same time, the 

 butterflies might all be presumed to belong naturally to the 

 same wet-season brood. It was remarkable that little or no 

 difference was perceptible between the specimens kept at the 

 ordinary temperature but in an atmosphere saturated with 

 moisture, and those of which the larvae were reared under 

 normal conditions, and the pupae had been iced. In both these 

 cases the under-sides of the resulting butterflies tended to as- 

 sume the macular appearance, the highest development of which 

 was characteristic of the form generally called gnoma. It 

 was also worthy of notice that the lowering of the temperature 

 in the latter case did not appear to have retarded the emergence. 

 But the aspect of the third row of specimens — those which had 

 been subjected to excessive dryness — was widely different from 

 that of the rest. Here, as shown by Major Manders' photograph, 

 the maculae were almost entirely absent ; and the butterflies, 

 or at all events the females, were of the form usually known 

 as pyranthe. In spite of the small numbers concerned, it could 

 hardly be doubted that this difference was significant ; and 

 the main result appeared, therefore, to be that while neither 

 moistvire nor cooling produced any alteration in the appearance 

 of the ordinary wet-season form, the exposure of larvae belong- 

 ing to the same form to an artificially dehydrated atmosphere 

 did cause them to assume the garb that was generally charac- 

 teristic of the dry months of the year. It was to be hoped 

 that the experiments might be repeated with larger numbers. 

 A point that seemed to require some explanation was that 

 whereas the au.thor of the present paper had no doubt that 



