( 6 9 [xiv 
“Tt will be remembered that some few years ago Mr. 
Marshall conducted certain experiments with a view to 
ascertain whether the assumption of the wet- or dry-season 
form of various African butterflies could be controlled by 
exposure in the pupal state to artificial conditions of tempera- 
ture and moisture. Some of the results of these experiments 
were recorded and discussed by Mr. Marshall in Ann. Mag. 
Nat. Hist., 1901, vol. ii, p. 398. Others were dealt with in a 
paper published in Trans. Ent. Soc. Lond., 1902, p. 189. Most 
of the material produced in the course of this research was 
exhibited on the occasion when the last-named paper was read ; 
the present specimens, however, though duly recorded in that 
paper, had not then reached the Hope Department. They 
were therefore not included in the comments added by me 
to Mr. Marshall’s account of his experiments, and they 
have not previously been seen by the members of this 
Society. This note and exhibit may accordingly be taken 
as a kind of appendix to the paper in the 1902 volume of 
our Transactions. 
“The specimens now shown are as follows :— 
“(1) Four specimens of Crenis boisduvalii, Wallgrn. 
“These form part of the series recorded by G. A. K. 
Marshall in Trans. Ent. Soc. Lond., 1902, p. 206. They consist 
of one ¢ reared under normal conditions; two 9 2 exposed 
in the pupal condition to excessive moisture; and one 9 
similarly exposed to dry heat. They accord fairly with the 
seven specimens of the same series, reared under correspond- 
ing conditions, which were presented by Mr. Marshall to the 
Hope Collection in 1897. The statements made (/oc. cit., 
p- 209) with regard to the original seven are confirmed by the 
new accessions, with the exception that the upper surface of the 
male kept in normal surroundings is perhaps somewhat lighter 
than that of the dry-heat male already in the Collection. The 
under surface, however, of this male, and the general aspect of 
all the females support the conclusion before arrived at that 
the intermediate or early dry-season form of this butterfly can 
be at least slightly influenced in the direction of the dry- or 
wet-season phase respectively by artificial conditions of dry 
heat and moisture. 
