ADDENDA. 
51 
the anterior fork-cell being twice as long as the posterior, and its stem much the shorter, though both 
stems are rather long, while the posterior is ver}- short, and but little :\ider than the anterior. 
Length, excluding the proboscis, 2.6 mm. 
Habitat. — Freetown, West Coast of Africa. 
Owing to the absence of ornamentation, the description of this species is necessarily brief, but 
it will, I trust, suffice to distinguish it from an)- neighbouring species. 
G. M. GILES, M.B., F.R.C.S., Major LM.S. 
ADDENDUM II. 
Obicrvatious at Fn-ctoivn^ Accra^ ami Lagos. 
By R. Flcldlng-Ould, M.A., M.B. 
\. SIERRA LEONE. 
In accordance with instructions I joined Major Ross at Sierra Leone in September last, and 
during the remainder of his staj- there co-operated \\ ith liini in his researches ; and later, \\ hen he 
returned to England, I continued the \vork of the expedition in Freetown. 
The habitat and "breeding puddles" of tiie Anopheles \\hich had been observed infesting the 
Wilberforce barracks we had been unable to discover, and I determined to make further and more 
rigorous search through the surrounding country than had been possible hitherto. In this I received 
the valuable assistance of Captain Smith, R.A.M.C. ; but, notwithstanding the most careful explorations, 
we were unable to find any Anopheles-h(fxx\x\<^ puddles nearer to the barracks than 1,500 yards. 'Fhose 
we found were more or less permanent pools in the crevices of rocks below Signal Hill ; and some 
others were found in Murray Town. I am inclined to think that these puddles are the puddles that 
supply the mosquitoes which infest the barracks. It has been observed that the Anopheles are only to 
be found in the barracks intermittentl)- — that is to say, a svsarm may be present for two or three days, 
and then for a week no mosquitoes are to be seen. This fact, and the impossibility of finding any 
puddles nearer than a mile, I venture to explain b}- the hypothesis that the wind is an important 
factor in the matter. The prevailing \\ind blows over the puddles that I have mentioned in the 
direction of the barracks, and by its means, when favourable, the mosquitoes may be able to travel a 
long distance — quite contrary to their ordinary habits. 
In support of this view it may be mentioned that many facts are on record which seem to 
indicate that the poison may be carried to some distance by winds. Again, it has been noticed that 
of the two banks of a stream in a malarious district, that towards which the prevailing winds blo\v is 
often the most affected. 
During the remainder of my stay in Freetown I was kept supplied by consignments of mosquitoes 
from the barracks, and I also obtained some from the houses of natives kno^vn to be suffering from 
fever. Dissection of these gave substantially the same results obtaineti by M.ajor Ross. I include with 
these notes some drawings, made on the spot, of microscopical preparations, \vhich show various phases 
of the malarial parasite in the gnat (Plate IV.) 
Out of 29 Anopheles examined by me, six, or 18 per cent., gave definite parasites; while 17 
Culex gave in every case negative results. 
I made experiments on the puddles at Freetown with both tar and kerosene as culicicides. 
Both these proved effectual as larva-destroyers, but the former is, in my opinion, 1ikcl\- to pro\e the 
