Papilio dardanus (merope) and Acrea johnstoni. 303 
pale buff. The resemblance of this striking and beautiful 
form is also promoted by its size; for it is one of the 
largest specimens of johnstuni which I have ever seen. 
As in so many other cases this mimic is an even closer 
approach to a co-mimic than it is to the primary model. 
And of all the species which are grouped round Planema 
pogget there can be no doubt that its resemblance is 
strongest to the planemoides female of Papilio dardanus 
(Plate XX, Figs. 2, 4). I do not know of this latter from 
Taveta where the (8) form of semifulvescens was collected 
by Mr. St. Aubyn Rogers; but p/anemoides exists in the 
A. H. Harrison collection from Nairobi, so that its exist- 
ence in the neighbourhood of Kilimanjaro and Taveta is 
at any rate probable; and the same may be said of 
Planema poygei, the primary model, also labelled Nairobi 
in the same collection. 
In both (a) and (8) sub-forms of semifulvescens the fulvous 
part of the fore-wing under-side would be hidden by the 
hind in the attitude of prolonged rest, so that the appear- 
ence becomes synaposematic with many of the smaller 
Acrvine rather than with the particular Planema models. 
On the other hand, in flight and probably during brief 
rest between successive flights the basal part of the fore- 
wing under-side would contribute to the visible appearance 
and serve to reinforce the resemblance to the Planemas. 
(vy) The third sub-form of semifulvescens is the toruna 
form (Plate XXII, Fig. 3a), described under that name 
from Toro, W. Uganda, by Mr. H. Grose-Smith. There 
can be no doubt I think that this is a further develop- 
ment of the form described by Oberthiir from Kilimanjaro 
—a modification brought about by mimetic resemblance 
to another Planema model,—?. latifasciata, K. M. Sharpe 
(Plate XXII, Fig. 3). It is altogether a much more perfect 
mimic of this Planema than semifulvescens (a) is of the 
allied 2. quadricolor. The rich brown colour of the basal 
half of the fore-wing is here alike in model and mimic, 
while the zigzag row of four spots tend in ¢orwna to fuse 
and generally completely fuse into a zigzag fulvous band 
somewhat resembling but more irregular than that of the 
Planema model. In P. latifasciata the black inner border 
of the fulvous band is far more feebly developed than in 
P. quadricolor, so that the absence of this border in torwna 
does not greatly detract from the likeness. On the other 
hand, the fulvous band itself is far wider and more con- 
