[-39 
THE INTERMEDIARY HOST OF FILARIA CYPSELI 
(annett, dutton, elliott) 
THE FILARIA OF THE AFRICAN SWIFT 
CYPSELUS AFFINIS 
Bv J. EVERETT DUTTON, M.B. 
WALTER MYERS FELLOW, LIVERPOOL SCHOOL OF TROPICAL MEDIC! N E 
WHILE staying at Bathurst, Gambia, on a mission sent to the colony by the 
Liverpool School of Tropical Medicine, in 1901, I had opportunities to 
extend the studies commenced in Nigeria, in 1900, by the members of the 
Liverpool Malaria Expedition sent to that colony by the Committee of the School. 
On my return from Bathurst, lack of time and opportunity prevented me from 
collecting together the facts acquired on the Gambian Expedition in anything like a 
concrete form, and, as the Committee of the School deemed it advisable to despatch 
another expedition to the Gambian colony, I thought it better to delay writing until 
I had made further studies on the subject of this present paper. During my second 
visit to the colony no further advance was made ; however, in view of its interest, 
and of the light that may possibly be thrown on the transmission of some of the 
human filaria, I propose to give here the life-historv of this bird filana as far as I 
have worked it out. 
The swift, Cypselus afjinis, is a very common bird on the West African coast ; in 
certain places it occurs in enormous numbers. It generally builds its nest near 
human habitations, in neighbouring palm trees, or on old walls, but more especially 
under the eaves and on the rafters of bungalows. The nests are built of mud and 
are lined with grass and a few feathers — often there are three to six nests in close 
proximity to one another. At night the birds sleep huddled together in their nests, 
the young birds staying with their parents for some time after they are able to fly ; 
it was an easy matter to obtain birds for examination after they had retired for the 
night. Generally two to six birds were found in each nest. 
Nearly all the birds examined were found to be more or less infested with a 
small biting louse, which Mr. F. V. Theobald 1 very kindly informs me belongs to 
(1). Dear Dr. Dutton. — All I can get out about the lice from swifts in W. Africa, that you sent me, is that they 
are Leiothinae — I cannot find the species, I am sorry to say, and most likely it is new. — Fred. V. Theobald. 
