OF THE NATIVE DOMESTIC WATER-RECEPTACLES AT LAGOS, &C. 129 



impossible without actual residence, as the mosquito of one house is not 

 always that of the next. The superior accuracy and finality obtained by dealing 

 with the larviB breeding in the native yards of the township is apparent, and I 

 hope that a similar examination of the larva; of each native town will be attempted. 

 We shall then be placed in a position to compare accurately the geographical 

 distribution of the mosquitos with that of the indigenous diseases. Very useful 

 information will, I feel sure, be obtained by such a comparison, for all the chances 

 are in favour of that insect, which breeds and lives in the immediate vicinity of 

 human dwellings, playing a preponderating part in the transmission of human 

 diseases. Such a study of the larva; would also supply the materials required for 

 the accurate identification of really distinct species ; a subject which is at present 

 in considerable confusion. 



The results obtained by 8 months' investigation are presented below in tabu- 

 lated form, and furnish some surprises. But to render the tables intelligible it 

 will be necessary first to explain shortly the geography of the places named in 

 them. 



The town of Lagos is built ujDon the islands of Lagos and Tddo, which are 

 connected by a long bridge. These islands are sandy, low-lying and swampy. 

 It will be seen on the map that the town is divided into 4 Sanitary Divisions, 

 A, B, C, D, each of which is sub-divided into districts lettered alphabetically. 



Ebute Metta is a town built upon the mainland, being joined to Iddo by a long 

 bridge. It is the headquarters of the Government Railway, and is surrounded 

 by swamps. 



During the eight months, August to March inclusive, 18 different species of 

 insect larvag, of which 6 were mosquitos, and 5 Crustaceans were found in the 

 native domestic water-receptacles examined, as shown in the following list : — 



Insect Larvae. 



Stegomyia fasciata, F. 

 Pectinopalpus fuscus, Theo. 

 Culex duttoni, Theo. 

 Culex tigripes \2iV. fusca, Theo. 

 Culex nigroco stalls, Theo. 

 Pyretoplionts costalis, Loew. 

 Chironomus (3 species). 

 Psychoda (2 species), 

 Drosophila (1 species). 

 EphemeridcB. 



Crustacea. 



Cyclops similUmus, Brady. 

 Daplmia sp. 

 Cypris (2 species). 

 Atthegella africana, Brady. 



