( xl) 
were shown, exemplifying the “wet season,” “dry season,” 
and “intermediate ” forms of the species, and selected from 
the Hope Collection by permission of Professor Poulton. 
With reference to the exhibit, Dr. Dixey remarked that 
although direct evidence as to the seasonal changes in these 
Neotropical species was at present scanty, the indirect evidence 
was strong; inasmuch as the range of variation here shown 
was analogous with that existing in certain African and 
Oriental species, whose seasonal relations had been put on a 
firm basis by the work of Watson, Barker, Marshall, and 
others. In every one of the present instances the ‘“‘ wet 
season” form tended to be more deeply coloured, and to have 
its markings on the underside more fully developed ; while 
the “dry season” form was usually smaller, had its forewings 
more sharply pointed, and was nearly or entirely devoid of 
markings on the underside. He stated further that where 
evidence of the date of capture existed, it accorded very fairly 
with the supposition that these variations bore relation to 
seasonal conditions, though of course more data of this kind 
were much needed. He had selected the specimens of each 
species so far as possible from the same locality, endeavouring 
thus to meet the possible objection that these varieties, several 
of which had been described as distinct species, might have a 
local rather than a seasonal significance. He added that by 
an “intermediate” form he meant simply one that came 
somewhere between the other two—not necessarily half-way. 
He was accustomed to use the term in a general sense as 
equivalent to the German “ Zwischenform,” not as conveying 
the idea of an arithmetical mean (Mittelform). 
The Presipent observed that the exhibit was of special 
interest, as affording the first recorded evidence of the exist- 
ence of seasonal dimorphism in Neotropical butterflies. 
Mr. G. T. Porrirr exhibited an extraordinary variety of 
Bombyx quercus, bred in June last by Mr. W. Tunstall, from 
a larva found near Huddersfield. The specimen was a female 
of deep chocolate colour, with the band very faintly traced in 
dark olive. He also showed a yellow variety of Anchocelis 
rufina from Wharncliffe Woods, West Yorkshire. 
Dr. Cuarpman, Mr. Luoyp, and Mr. Nicuotson exhibited 
