OF THE NATIVE DOMESTIC WATER-RECEPTACLES AT LAGOS, &cC. 135 
Cypris (2 species). 
Species of this genus occurred in an average of 1°3 per cent. of the total 
receptacles. These Ostracods have been found in Europe to harbour Tenia, 
Trematode larve and Acanthocephalus, and therefore deserve further attention. 
Daphnia sp. 
Specimens of this genus were found in only 2 out of 1,043 receptacles examined. 
Atthegella africana, Brady. 
This species was present in large numbers but only in one receptacle examined. 
It was originally found by me in the Gold Coast. 
SUMMARY. 
1. The examination of the contents of the domestic water-receptacles was 
found to be a practical and accurate method of studying the mosquito fauna of a 
township. 
2. During the investigation the following points were found to be of 
importance :-— 
The Division and District of the township; for in Lagos conditions differ 
in different Divisions. 
a. 
(3. The variety of water-receptacles (deep or shallow); for some larve 
prefer barrels to pots, and vice versa. 
The nationality of the householder. The food of the different nationalities 
differs, and water-vessels usually contain particles of food upon which 
larvee may be observed to feed. 
6. The extent of the distribution (Coast line and Inland), The water on 
the Coast line is mostly brackish, that of the interior is usually almost 
free from chlorides. 
nye 
3. A seasonal variation in numbers was shown to occur, but the causes were 
obscure. 
4, Sensitiveness to change of environment was found to exist in some cases, 
and in one was supposed to depend upon the amount of chlorides. 
5. Two active natural enemies of mosquito larve were found to exist. 
6. It was found that both larve and pup were killed by raising the temperature 
of the water above 45° C, 
7. Stegomyia fasciata was found to be the commonest mosquito and very widely 
distributed. 
20419 Dz2 
