818 DR. A. G. BUTLER ON LEPIDOPTERA Nov. 17 
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“So far as I know, only two Europeans have ever visited Senga 
besides myself, one of whom was poor Mr. Glave, who died lately 
when crossing the continent from east to west. No one, I think, 
has ever done any natural history collecting there. 
“In August and September last I had occasion to make a 
journey into Senga, for the purpose of investigating the slave- 
trade, and this afforded me an opportunity of shooting and natural 
history collecting. 
**] got together a number of Antelopes’ heads, some land-shells, 
and about sixty species of Butterflies—some of which I take to 
be new, for I have never before seen anything like them. Had 
the state of the country permitted it, 1 would have prolonged my 
journey and done more; but the Senga slave-traders proved 
hostile: twice we were fired on; and, having no fighting force at 
my disposal, I was obliged to retrace my steps. 
‘“‘ However, everything taken into consideration, I am well 
pleased with what little I got; the Butterflies certainly are very 
interesting, and will furnish, I should think, six or seven new 
species, if not more. 
“ Returning from Senga, then, I revisited Henga (33 days S.W. 
from this), and there I spent about six weeks for the purpose 
of shooting. It was nota good time of year for insects, being just 
the end of the dry season: however, I took a few, one a large 
spotted ‘ Blue’—the largest ‘Blue’ I think I ever saw, but not 
anything gorgeous, which may be something good. This and one 
or two other insects I will send you, all in the same box.” 
We had commenced mounting the Butterflies in this very 
interesting consignment when Mr. Crawshay reached England, 
bringing with him two other boxes of Lepidoptera collected by 
him in or near the Deep Bay district. I have therefore thought it 
best to combine the account of the two collections in one paper. 
As, of late years, the minds of Lepidopterists have been greatly 
exercised respecting the seasonal forms of Butterflies, I asked 
Mr. Crawshay whether he could give me information respecting the 
duration of the wet and dry seasons in British Central Atrica. 
He now sends me the following particulars, which will doubtless 
prove of considerable value to the students of dimorphism :— 
“No precise limit can be laid down to define the rainy and 
dry seasous throughout the whole of British Central Africa. The 
seasons vary in the various localities: in the first place, latitude 
has to be taken into consideration ; then, again, the rains of the hills 
set in earlier than those of the plains. 
“In the Shiri highlands, which on the mean are over 3000 feet 
alt., the first rains fall about the end of September or the beginning 
of October, according to the phase of the moon; these are the 
preliminary rains, and they last only two or three days, as a rule. 
Then succeeds a dry period of some three weeks or so. After 
this the heavy rains set in, and continue until the middle or end 
of April—some years a little earlier or later than this. 
“This year I happened to be at Blantyre at the end of April 
