818 DE. A. G. BUTLER ON LEPIDOPTEEA [Nov. 17, 



" So far as T 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. 



" 1 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, I 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 (3| days S.W. 

 from this), and there I spent about six weeks for the purpose 

 of shooting. It was not a good time of year for insects, being just 

 the end of the dry season : however, I took a few, one a large 

 spotted 4 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 Africa. 

 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 seasons 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 



" 



