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Crab-holes, Trees, and other Mosquito Sources in Lagos

Published online by Cambridge University Press:  10 July 2009

J. M. Dalziel
Affiliation:
Senior Sanitary Officer, Gold Coast.

Extract

The occurrence of mosquitos in crab-holes is tolerably well known both in West Africa and in other countries. It is doubtful, however, whether these sources receive sufficient practical attention, and one hears too often when their presence is demonstrated the opinion expressed that the insects only shelter there and are not likely to use them as breeding-places when so many others are available. One has even found medical officers whose unbelief had to be assailed by demonstration of the larvae and pupae. Others again, though aware of the fact, perhaps think the occurrence of too trifling importance to justify the necessary steps to eradicate them, even when near a dwelling.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1920

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References

* I have to thank the Director, Dr. A. Connal, for undertaking their investigation and Mrs. Connal for identifications of the numerous mosquitos obtained from these and from various other sources.

* This plant is an ornamental shrub of the Nat. Ord. Liliaceae, and is commonly planted along boundary fences in the coastal regions throughout West Africa. In Nigeria its Yoruba name is piregun and obtanically it is Dracaena fragrans, though possibly other species may be included. Its popular names refer to the decorative use made of the leaves by the Sierra-Leonians on festive occasions. J.M.D.

* Reference may be made to salt-water species occurring elsewhere:—Acartomyia (Aēdes) zammitti, seems to live only in pools left after high water (Dardanelles). Stegonocops sp. and Aēdes fluviatilis (Culex fluviatilis, Lutz) ‘occur in rock-pools with concentrated sea-water (Panama). Culex sollicitans, Walk., is almost confined to salt pools near sea-beaches (Howard, Dyar and Knab, “The Mosquitoes of N. and Central America and the W. Indies,” i, p. 150). C. sollicitans, Walk., occurs in the mud of salt marshes (India, Karachi). Culex (Aēdes) cantator, Coq., C. taeniorhynchus, Wd., C. salinarius, Coq., with C. sollicitans, are found in the coastal salt marshes of America (Connecticut, etc.). Species of Taeniorhynchus and Anopheles occur in brackish marshes and mangrove swamps, and Anopheles subpictus (rossi) in brackish wells and salt-water tanks (India). A. (Pseudomyzomyia) ludlowi, a malaria carrier in the Andamans, breeds in salt swamps and mud flats. Anopheles multicolor. Camb. (Pyretophorus sp.) was found in Egypt in water with 2.56 to 3.25 per cent. NaCl (Willcocks, Ann. Trop. Med. Paras. iii, 5, pp. 586–587).

* Pectinopalpus fuscus, Theo.= Culiciomyia nebulosa, Theo. ; and Culex nigrocostalis Theo.= Culex decens, Theo.

To these 46 may be added 10 species absent from this list but included amongst the 41 species recorded from Lagos and published in the pamphlet of the Yellow Fever (West Africa) Commission, “Distribution of Mosquitos in West Africa,” Aug. 1913, viz. Anopheles pharoēnsis, Theo., A ēdomyia africana, N.L., Banksinella lineatopennis, Ludl., Eretmopodites inornatus, Newst., Mimomyia mimomyiaformis, Newst., Ochlerotatus longipalpis, Grünb., O. marshalli, Theo., Stegomyia apicoargentea, Theo., Toxorhynchites brevipalpis, Theo., Uranotaenia mashonaensis, Theo.