306 Professor E. B. Poulton on Adimetic Forms of 
We see therefore that Aurivillius keeps A. lycoa distinct, 
while he suggests that A. fallax (kilimandjara) may be a 
form of johnstoni. I believe that he is right in this last 
opinion, although positive proof can only be gained by 
breeding ; but the facts set forth below render it certain 
that fallac i is the eastern form of dycoa. If Aurivillius is 
right in his association of fallax it will inevitably follow 
that the whole series of varied forms must fall under 
Godart’s species,—/ycoa. 
Acrvxa lycoa of the tropical west coast is distinguished 
from A. johnstoni by the following characteristics :— 
(1) The large size of the four spots on the fore-wing 
and the tendency of the subapical pair to fuse and form 
a subapical bar: the tendency of the more interior pair 
similarly to form a patch extending from below the end of 
the cell towards but not quite reaching the posterior angle 
of the wing. The spots are, however, “sometimes separate, 
although much lar ger and more nearly approximated than 
in johnstoni. 
(2) The pronounced sexual dimorphism of which no trace 
can be found in johnstoni. The males of lycoa have a 
much browner ground colour than the females, especially in 
the hind-wing, while the spots of the fore-wing are pale 
buff instead of white and are sometimes evanescent. 
Furthermore the white discal patch of the hind-wing is 
unrepresented in those males I have had the opportunity 
of examining, while the development of the internervular 
radii is correspondingly increased. 
(3) The apex of the fore-wing of /ycoa is more broadly 
rounded and the costal margin more curved than in 
johnstont. ‘The outline of the wing between the apex 
and the posterior angle is straight or even convex in the 
females, straight or very slightly concave in the males. 
In A. johnstoni it is probably always concave, although 
sometimes very slightly so. 
(4) The basal black spots on hind-wing under-side are 
maller in /ycoa and less concentrated towards the extreme 
base of the wing. The spot in the base of the cell with 
the two spots on the costal side of it forms in lycoa a 
characteristic approximately equilateral triangle. Owing 
to the greater concentration of spots the corresponding 
triangle in johnstont is nearly always isosceles with its base 
towards the root of the wing. It is moreover less con- 
spicuous as a feature in the wing of this latter form. 
