CRAB-HOLES, TREES, AND OTHER MOSQUITO SOURCES IN LAGOS. 



257 



The commonest shade or ornamental trees planted or found growing naturally 

 in Lagos are banyans (several species), mango, flamboyant, West Indian almond, 

 Egyptian acacia and rain tree. Of the non-indigenous trees the flamboyant seems 

 to be the most liable to rot-holes either in the fork or in the stump of a cut branch, 

 and these holes generally retain water. The following list gives the names of the 

 trees in which mosquito larvae were found ; in two cases no record was made of 

 the kind of tree by the finder. 



Table III. 



Common Name. 



Botanical Name. 



Number of Occasions. 



Banyan (4 species) 



Flamboyant 



Mango 



Pawpaw 



Woman's Tongue or Egyptian 



Acacia . . 

 " Miraculous Berry 



— aghayun) 

 Almond Tree 

 Black or Velvet Tamarind 

 Eain Tree . . 

 Breadfruit 

 Guava 

 Akee Apple 

 Queen of Flowers 

 (Yoruba — akoTco) . . 

 Cashew 



(Yoruba 



Alexandrian Laurel 



Orange 



Cock-hat Tree (Yoruba — piregun) 

 Coconut 



Ornamental Amaryllid . . 

 Ornamental broad-leaved Screw- 

 pine 

 Ornamental striped Screw-pine . . 



Ficus thonningii 

 a platyphylla 

 „ populifolia 



,y Sp. 



Poinciana regia 

 Mangifera indica 

 Carica papaya 



Alhizzia lebbelc 



Sideroxylon dulcificum 

 Terminalia catappa 

 Dialium guineense 

 Enterolobium dulcis 

 Artocarpus inc^sa 

 Psidium guayava 

 Blighia sapida 

 Lagerstroemia regina • 

 Newbouldia laevis 

 Anacardium occidentale 

 StercuUa barteri 

 Calophyllum inophyllum 

 MilleUia sanagana 

 Citrus aurantium 

 Dracaena fragrans 

 Cocos nucifera 

 Crinum giganteum 



Pandanus pacificiis 

 Pandanus veitchii 



22 



13 

 6 

 5 



The five species last named have not proved to be of as much importance as 

 might be expected in Lagos with an average annual rainfall of about 75 inches, 

 the number of larvae found under conditions likely to ensure full development 

 being small. A notable absence from the list is the banana plant, which appears in 

 some places to be a likely and important habitat. Possibly bananas have received 

 less direct attention in Lagos than they deserve, but a good many trees have 

 at different times come under my own observation without one positive find. 

 On the other hand the stump left in the ground after removal of the decayed stem 

 is an abundant and often neglected source of S. fasciata. The pawpaw is a source 

 which is apt to be overlooked. The stem substance is soft and quickly decays, and 

 a stump or cut branch containing a rotting hollow is soon concealed by the foliage 

 of fresh young shoots. Also the stem of the healthy tree is hollow with incomplete 

 partitions. A lateral perforation, caused probably by an insect, is frequently 

 present and allows access to mosquitos. Sources of such a nature may remain 



