Dr. G. D. Hale Carpenter on Pseudacraea boisduvali. 651 
A further complication is introduced into this intricate 
question by the interrelation between the two species of 
Acraea themselves and their place in a large combination 
of dark fore-winged Acraeas in West Africa. In this 
combination egina is probably the predominant form, and 
has played the principal part in the Western modification 
of zetes. Thus, in the Western ¢ zetes (Plate XXXVII, 
fig. 5) the red area of the fore-wing is much contracted, 
resembling the smaller area of egina (fig. 1). Specimens 
of this kind occurred on Bugalla Island (fig. 7), some show- 
ing it even more markedly than the one figured. Others, 
however, were still of comparatively Eastern form (fig. 8), 
so that, on Bugalla Island, there was a true mixture of the 
two geographical races, as is so often found in Uganda 
where Hast and West do meet around the shore of the 
great Lake Victoria. 
It may be noted that on Bugalla itself egina and perhaps 
perenna, D. and H., are the only Acraeas which are likely 
to have taken any part in the transformation of zetes. 
It will be of interest here to note the gradual develop- 
ment of our knowledge of the relationship between Pseud- 
acraea borsduvali and its Acraeine models. Trimen says, 
in an appendix to Rogers’ paper mentioned above, 1908, 
p. 552: ‘in 1869 (Trans. Linn. Soc. Lond., xxvi, p. 517),” 
and later in 1887 and 1889 (“S. Afr. Butterflies,” 1, p. 298; 
il, p. 405), “I showed how closely in both sexes trimenii, 
the South-Eastern form, copied Acraea acara, Hewits., of 
the same region, just as boisdwvalii mimicked the West 
African Acraea zetes, Linn.” Later on he continues 
(p. 553): “Iam now able, . . . to record the occurrence 
in a British East African series... of a 3g trimenii 
from ‘Rabai, near Mombasa (K. St. A. Rogers) .. .,’ 
in which the sub-apical bar of fore-wing is very much 
reduced and narrowed (while the red spots in the hind- 
marginal border of hind-wing are unusually large),—having 
the fore-wing fuscous suffusion largely developed, so that 
the usual red ground colour is obliterated except for a 
large sub-quadrate space at posterior angle as in P. boisdu- 
valu, and a slight sub-basal trace. This example is a 
most distinctly intermediate link between the Western and 
Hastern forms . . .” 
In a footnote he adds: “ Haase (Untersuch. iiber die 
Mimicry, etc., 1893, p. 43, taf. 4, ff. 26-28) showed that 
boisduvalia mimicked A. egina, Cram., more closely than 
TRANS. ENT. SOC. LOND. 1913.—PaRT Iv. (MAR. 1914) UU 
