Pere oe ee eee en ees ee 
his) Seal AE ag sca ae Sah 
} 
ss 
Ixil 
times in great numbers and on Dec. 5, 1920, the afternoon of 
the day before the Cicada observation, we came on a bare tree, 
apparently also Combretum, in the same woodland formation 
[see p. Ixiv], the twigs of which were literally covered with 
Inbythea, some resting, some flying off and back to the tree. 
It rather reminded me of my Amawris observation at Dar-es- 
Salaam, but the congregation was certainly not for shade, 
for it was one of the least shady spots and the afternoon was 
very dull with rain threatening. Had a brood lately emerged 
at and about a food-tree there,—were they congregating to 
facilitate mating or what? In Rhodesia I used to get it 
chiefly in and on the outskirts of primary forest. Here [at 
Kilossa] we get it in open Combretum and Brachystegia wood- 
ing and in great numbers at damp ground beside my house, 
in an open clearing. Why this difference? It seems obvious 
that shade is not the factor that determines the butterfly’s 
presence. It may be the presence of food-plant. Its remain- 
ing in numbers for long together 50 yards from the nearest 
trees or shrubs is also interesting in view of its protectively- 
coloured under-side. 
“ Jan. 2, 1921.—Still not posted! I caught a long series 
of Libythea to-day, being Sunday, and seeing that I got them 
50 at a time in my net! The variation of the under-sides is 
most interesting, and, like that of the still more variable 
Catocaline moth, Achaea lienardi Boisd., runs to definite 
patterns and a limited number of them, and the breeding 
I am sure is on ‘ Mendelian’ lines. Also I am sure this varia- 
tion is of use to the insect, since it prevents birds getting 
accustomed to looking out for a particular type of dead leaf 
or protective pattern.* I had some experimental evidence 
in favour of this view. 
“The Libytheas settle in huge numbers where the boy 
washes the clothes (soap is distributed around) and where 
cement has been thrown out. Is it possible that alkali is 
needed by them? ” 
THE COURTSHIP OF THE CrcaDA, MONOMATAPA INSIGNIS 
Dist. (TIBICINAE), OBSERVED IN TANGANYIKA TERRITORY.— 
Prof. Poutton said that he had received the following notes 
* See Poulton: ‘‘ Essays on Evolution,” Oxford, 1908, p. 310. 
