(¢ Give”) 
Not only is there this extraordinary difference in the pro- 
portions of the models, but the proportions of the mimetic 
forms to one another are also remarkably different from those 
of the mainland, terra being far more predominant over 
hobleyi in the island than hobleyi is over terra on the 
mainland. 
2. Proportion oF ‘TRANSITIONAL FORMS BETWEEN THE 
Mimetic PsrupacrabAS HIGHER ON THE ISLAND THAN ON THE 
Maintanp.—The table on p. xcii. shows a quite unusual number 
of transitional forms. Transition is indicated in various 
directions,—between ferra and obscura, between terra and 
2 hobleyi, between terra and ¢hobleyi, between obscura and 
? hobleyt. 
3. PosstpLe Causes or THE ABOVE DirFERENCES.—It is highly 
improbable that these remarkable differences are connected 
with climate or season of the year; for the contrasted sets of 
captures were made in almost the same months. The period 
was, moreover, long enough to exclude the effects of the 
seasons beginning and ending on different dates in different 
years. The most probable explanation appears to be that, 
in the condition of the jungle on Damba Island, there is some- 
thing unfavourable to Planemas, and that, in the absence or 
relative scarcity of the models, the mimetic resemblance of the 
Pseudacraeas is no longer rigidly maintained by selection. 
The pattern of Ps. terra is found among the protean mimetic 
forms of ewrytus, L., on the west coast, and even the colour as 
well as the pattern in a Nigerian mimic of the male Pl. epaea.* 
I suggest that in an area where these mimetic patterns are less 
strongly selected, there is a tendency, checked elsewhere, for 
them to run into each other, and also to move in the direction 
of the western ewrytus forms, from which there can be little 
doubt that the mimetic Pseudacraeas of Uganda originally 
developed. It is to be hoped that Dr. Carpenter may be able 
mimics, and he had not at the time learnt to distinguish them from their 
models. He states in a letter dated Dec. 5th, 1911: ‘‘I was much 
surprised to hear that I had sent more Pseudacraeas than Planemas, and 
thought I had done the opposite.” —E. B. P. 
* Figured by Dr. Karl Jordan in the publication of ‘‘I. Congr. Internat. 
d’Ent.,” 1910, Vol. II, pl. xxii, fig. 22a. Good examples of. pattern but 
not colour resemblance are shown in his pl. xxiii, figs. 26a, 27a. 
