xiv] (5) 
while in combination they could effect a transformation to the 
full wet-season form, the employment of the latter only with- 
out the former produced an entirely different result, the most 
distinctive mark of the new form being the accentuation of a 
feature usually characteristic of the dry season. 
XViii 
Wednesday, March 20th, 1907. 
Exhibition. 
PARALLELISM BETWEEN THE GENERA PurissuRA AND MyLo- 
TtHRiIs.—Dr. F. A. Drxry exhibited several species of Phrissura 
and Mylothris side by side, in order to illustrate the remarkable 
parallelism that exists between these two Pierine genera. 
The forms shown were as follows :— 
Phrissura lasti, Grose Smith, ¢  fylothris narcissus, Butl., 3 
P. sylvia, Fabr., 3 M. spica, Mosch., ¢ 
P. sylvia, Fabr., 2 M. spica, Mésch., ? 
P. sylvia, Fabr., ¢ (western MM. bernice, Hew., 3 
form) 
P. perlucens, Butl., 3 M. asphodelus, Butl., 3 
P. phebe, Butl., 2 M. poppea, Cram., 9 
P. phoebe, Butl., 2 M. poppea, Cram., 3 
P. phebe, Butl., @ M. rubricosta, Mab., @ 
The genus Phrisswra, he remarked, was closely akin to 
Appias, Tachyris, Catophaga and Glutophrissa ; Mylothris, on 
the other hand, occupied an isolated position and was of 
xix| 
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 Phrissura 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 
