258 J. M. DALZIEL. 



unnoticed for weeks or months and are commonly situated close to dwelling-houses. 

 The vertical depth of the cavity in the interior of a pawpaw tree which was 

 discovered to be the source of S. luteocephala and C. nebulosa captured in a 

 neighbouring bungalow, was found on cutting it open to be 6 feet. 



The number of different species of trees harbouring either S. luteocephala 

 or S. fasciata or both is considerable, and as regards the latter there is perhaps a 

 predilection for banyans. Out of 33 occasions when S. luteocephala was identified, 

 13 were from banyans (12 from the commonest species, viz., F. thonningii) and 8 

 from the flamboyant. The occurrence of the different mosquitos in respect of trees 

 was as follows: — 



S. luteocephala in banyans, 13 ; flamboyant, 7 ; mango, 3 ; Egyptian acacia, 3 ; 

 miraculous berry, 2; rain tree, 1 ; velvet tamarind, 1 ; almond, 1 ; cashew, 1 ; pawpaw, 1. 



S. fasciata in banyans, 6 ; flamboyant, 3 ; mango, 1 ; Egyptian acacia, 1 ; 

 breadfruit, 1 ; Sterculia barteri, 1 ; coconut, 1 ; screw-pine, 1. 



C. nebulosa in banyan, 1 ; pawpaw, 1. 



C. decens in banyan, 1 ; flamboyant, 1. 



0. apicoannulatus in Egyptian acacia, 1. 



Z7. annulata in screw-pine, 1. 



Collateral observations on tree-breeding species in West Africa are referred to 

 here for convenience of those interested in the subject. 



Sierra Leone (fide Bacot, loc. cit, supra). — In Freetown the " Cock-hat " tree 

 or " Cockade Bush "* holds sufiicient water in the axils and central leaf -whorl 

 (in the same manner as the pineapple and other plants) to be a likely source 

 of mosquitos. The breeding-place of two species in Freetown, viz. Uranotaenia 

 ornata, Theo., and Eretmopodites dracaenae, Edw., seems to be restricted to this 

 plant and to the similar conditions to be found in the coco-yam and the banana. 

 Other species yielded by the " Cock-hat " tree are S. simpsoni, and occasionally 

 S. fasciata and C. nebulosa. 



The silk-cotton tree affords in hollows enclosed by the buttresses and amongst 

 its spreading roots breeding-places for the following : — S. fasciata, S. simpsoni, 

 S. luteocephala, 0. minutus, 0. apicoannulatus, C. nebulosa, A. costalis, and C. decens. 



The coco-yam [Colocasia antiquorum) yielded most commonly S. simpsoni and 

 U. ornata ; also C. nebulosa and S. fasciata, and a few E. dracaenae. S. simpsoni 

 was found in banana plants, and S. fasciata in numbers with a few E. dracaenae in 

 the sarsaparilla [sic). 



Gold Coast {fide Ingram and Macfie, Bull. Ent. Res. vii, 1916, p. 3 ; viii, 

 1917, pp. 137, 145, 146). — The flamboyant has yielded most samples in Accra, but 

 mango and other trees are also sources. Five species of Stegomyia, viz. S. luteoce- 

 phala, S. fasciata. S. metallica, S. simpsoni, and S. unilineata, have been found, 

 generally several species in association with each other or with 0. apicoamndatus, 

 Edw. Larvae of Cyathomyia fusca, Theo., were obtained from a flamboyant trea 



* 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 iBpiregun and botanically 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. 



