(CO Mest) 
Mr. Barker’s paper was soon followed by one of equal 
interest * contributed to our “Transactions ” by Mr. G. A. K. 
Marshall, who has a most wide and intimate knowledge of 
butterfly-life south of the Zambesi. Mr. Marshall, after ex- 
pressing his concurrence with Mr. Barker’s opinions on the 
subject, proceeds to criticise with justice Dr. A. G. Butler’s 
rather random suggestion fT that in the Acreine the presence 
of a broad apical black patch on the forewings indicates a 
wet-season form, proving this idea to be wholly untenable, at 
any rate in three of the five cases advanced by Dr. Butler. 
He goes on to indicate the signs of seasonal variation in nine 
species of Acrea, and notably in the Mashunaland 4, halali, 
where both sexes vary strongly, and unlike the other known 
cases in the genus, have the black spots larger in the dry- 
season than in the wet-season form. To the numerous in- 
stances given by Barker he adds two more in Mycalesis and 
eight more in Precis. The latter are shown to offer a 
beautiful series of gradations in dimorphism, from the four 
species P. natalica, P. elgiva, P. tugela and P. artaxia, where 
—in addition to larger size and more falcate forewings—the 
. dry-season change is almost limited to the dull withered-leaf 
colour and marking of the underside ; then to the two species 
P. ceryne and P. archesia, where the upperside as well pre- 
sents considerable alteration both in colour and marking ; 
and finally, to the species P. stmia and P. octavia-natalensis, 
where the suggested respective dry-season forms P. cwama 
and P. sesumus present such extreme disparity in the aspect 
of both upper and under sides as to render it almost incred- 
ible that they can belong to the same species as the two wet- 
season forms in question. 
The actual rearing of the dry-season form of Terias zoe 
from eggs laid by the latter, and its proving to be (as had 
long been anticipated) the butterfly known as 7’. brigitta, is 
recorded in this paper on the authority of that practised 
collector and observer, my friend Mr. J. M. Hutchinson, of 
* «Notes on Seasonal Dimorphism in South-African Butterflies.” 
(Op. cit., 1896, p. 551.) 
+ Trans. Ent. Soc., Lond., 1895, p. 519. 
= 
bo 
