G ie) 
doubtful affinity. With the exception of two eastern forms, 
the species of Phrissura, like those of Mylothris, belonged to 
Africa. It was remarkable that there scarcely existed a 
single form of Phrissuwra that did not find a counterpart in 
the other genus, though there was nothing but a remote 
relationship between them. The forms that so closely 
resembled each other were, speaking generally, inhabitants 
of the same districts, and it was interesting to observe that 
where a species of the one genus underwent a local modifica- 
tion, the corresponding local race of the other genus was 
similarly transformed in appearance. Thus the Uganda form 
of P. sylvia, 3, closely resembled JZ, spica, ¢, from the same 
region, both being white butterflies with a dark apex to the 
fore-wing, a row of marginal black spots on the hind-wing, 
and a basal patch of bright orange. In the representative 
forms from the Congo region, P. perlucens, Butl., ¢, and M. 
asphodelus, Butl., 3 , the basal orange was in each case replaced 
by lemon yellow. Again, in the West African specimen 
shown of P. sylvia, 5, the basal orange took on a darker tinge 
and was somewhat modified in shape, in both of which respects 
it came into close correspondence with J. bernice from the 
same locality. The facts might lend some apparent colour to 
the view that the correspondence was due in each case to 
similarity of surroundings. The speaker, however, thought 
that the difficulties in the way of such an explanation were 
insuperable, and that the relation was in every case mimetic. 
It would not be easy to say whether the mimicry was of the 
Batesian or of the Miillerian kind, the data being scarcely 
sufficient ; he inclined personally to the belief that it would 
prove to be of the latter, 7. e. the Miillerian sort, especially as 
there appeared to be indications of a diaposematic exchange 
of characters between the two series of forms. 
He regretted that the Hope Collection possessed no speci- 
mens of P. nyasana, Butl., ¢, for this form together with 
M. riippellii, Koch, 6, would have made a striking addition to 
the exhibit. He should have preferred also to put a specimen 
of the West African P. isokani, Grose Smith, ? , beside the I. 
poppea, 2, from Ashanti, had one been available. 
Though he had on the present occasion confined himself to 
