( cxxxix ) 



out of the fourteen males captured in 1911 were much darker 

 than any of the eight males captured in 1912. The copper 

 tint of the eight 1912 females was more brilliantly lustrous 

 than in the seven 1911 females. It was interesting that the 

 effects were similar in kind in the two sexes, although very 

 different in degree, also that the females, in which the differ- 

 ence was but slight, were more uniformly affected than the 

 males. 



PoLYOMMATUS ICARUS Femalbs. — Mr. T. H. L. Grosvenor, 

 who was present as a visitor, exhibited a series of P. icarus 

 females principally from various localities on the North Downs, 

 arranged according to the year and emergence to which they 

 belonged, with the intention of showing the seasonal di- 

 morphism of the females of this species, and also with the idea 

 of raising a discussion on the theory originated by the late 

 Dr. G. G. 0. Hodgson, as to whether the climatic or atmo- 

 spheric conditions prevailing at the time of emergence, or at 

 an earlier period of its existence, do, or do not tend to 

 increase or decrease the sexual dimorphism. From his own 

 experience among the Lycaenids during the past ten years, 

 the conclusion was forced upon him that a hot summer pro- 

 duces as a prevailing form the brown type, with little or no 

 blue scaling. One could not, of course, make a dogmatic 

 statement to this effect, as assiduous selective collecting 

 would always produce the blue form in greater or less numbers, 

 whereas, in a cold wet summer the prevailing form was 

 found to be more or less heavily scaled with blue. He could 

 not quite agree with Hodgson that the sexual dimorphism is 

 decreased or accentuated by the sexes approximating to an 

 imaginary intermediate form, especially so in the species 

 under discussion, where, if there were any tendency in this 

 direction, the variation of the males would be so subtle that 

 no reliable inference could be drawn. In the case of Agriades 

 corydoii this might be possible owing to the more decided 

 variation of the males. In his own opinion a decrease of 

 sexual dimorphism, or the contrary, could be produced by 

 variation of one sex towards or receding from the type of the 

 opposite sex. 



He could not but regret that he had not access to Hodgson's 



