UNSUSPECTED BREEDING-PLACES 167 



with Stegomyia larvae. British Honduras exports 

 much logwood, and the water that collects in the 

 depressions of the logs on the wharves, though 

 purplish-black and highly astringent, contains larvae 

 in large numbers. Large water-vats are in common 

 use in Central and South America. They furnish 

 favourite breeding - grounds. Some West Indians 

 endeavour to protect their flower-beds from the 

 attentions of the umbrella ants, and the little ditches 

 used for this purpose do far more harm than good. 

 The ants may be circumvented, but a plague of 

 mosquitoes replaces them. Rot holes in trees, water 

 holding epiphytes, inverted bottles (used for borders 

 in some parts of Africa), roof gutters, and, above all, 

 discarded bottles, crockery, and tins of all sorts 

 provide innumerable opportunities for the breeding 

 of mosquitoes. Immense numbers of cans, used for 

 tinned food, are found in districts in West Africa 

 opening up to commerce, and as Sir Rubert Boyce 

 wrote : " A veritable tin-can invasion extends up from 

 the coast towns into the interior villages. The more 

 traders the more tin cans." In other countries, also, 

 the same thing is observed. The water-holding 

 capacity of these discarded utensils is enormous, and, 

 to complicate matters, they are not always obvious, 

 being concealed in the weeds and low bush im- 

 mediately about the houses and in the compounds. 

 Protected by the foliage from the sun, and easily 

 filled by rain showers or by drippings from the foliage, 

 they are ideal for the mosquitoes, which breed there 

 freely. Thus it is seen that the breeding-places of 

 the Stegomyia are artificial to an enormous extent, 



