EXPLANATION;OF PLratE XXXVIII. 
The figures are slightly under ? of the natural size. 
The Nymphaline butterfly Pseudacraea boisduvali and its Acraeine 
model Acraea egina on Bugalla Isle, Lake Victoria, nearly 4000 ft. 
above sea-level. 
The males of both model and mimic are of the Western type of 
pattern. The female model is a remarkable pale form peculiar 
to the island, but recalling the female of Prince’s Island in the Gulf 
of Guinea. The Bugalla females of the mimic exhibit various 
degrees of approach to the pale egina females. 
All the examples here represented, except that shown in fig. 5, 
were captured by G. D. H. Carpenter. 
Fie. 1. Acraea egina 3. Open grass-land, June 7-14, 1912. The 
model for 2,6, 7. Pattern resembles that of Western 
male (Plate XX XVII, fig. 1). 
2. Ps. boisduvali 3. Forest edge, lake shore, March 12, 1912. 
Mimic of 1: the pattern is more Western in character 
than 6 and 7 in the almost complete absence of the 
subapical bar of the fore-wing. 
3. Acraea egina 9 form alba, Eltringham. Forest edge, 
Aug. 9, 1912. 
4. Acraea egina, 2 form alba. Forest edge, Aug. 16. 1912. 
Figs. 3 and 4 are the models for 9 and 10. These are 
two of the four alba forms alluded to in the text 
which so very closely approach 5, and differ from the 
Western mainland female (Plate XX XVII, fig. 3.) 
5. Acraea egina, subspecies medea, Cram., 9. Prince’s Island, 
W. Africa, March 30, 1901. 
6. Ps. boisduvali 3. Forest edge, Dec. 24, 1912. Mimic of 1. 
Intermediate between 2 and 7. 
7. Ps. boisduvali . Forest edge, Sept. 5, 1912. An interest- 
ing transitional male: it has the yellow subapical area, 
which is much more developed in the Eastern trimeni 
form, but possesses also the basal black suffusion of the 
Western form, the true boisdwvali. It thus combines 
Eastern and Western characters. Cf. 2 and 6. 
8. Ps. boisduvali 2. Forest path, Jan. 5, 1913. The specimen 
which-comes nearest to the typical Western form, having 
no white suffusion and very little pink suffusion over 
the brown. 
9. Ps. boisduvali 9. Forest path, March 10, 1912. This 
specimen, intermediate between 8 and 10, shows a 
moderate amount of white suffusion, mimicking 3 and 4. 
10. Ps. boisduvali 9. Forest edge, lake shore, Sept. 27, 1912. 
This one, of all the females, best shows the white suffusion 
which produces likeness to 3 and 4. 
