218 MOSQUITO LARViK AND THEIR NATURAL IINEMIES. 



fact tliat it is the only species o£ fish in the island ; its capacity for with- 

 standing competition is therefore not likely to be great. 



The idea of distributing dragon-fly larvse or water-beetles for the de- 

 struction of mosquitos would appear to be less promising. For these widely 

 distributed insects would be capable, during their winged stages, of gaining 

 access to every suitable piece of water in a given neighbourhood ; and there- 

 fore their absence from any pool would probably mean that it Avas unsuitable 

 for their larvse. Such an argument would not necessarily apply to fish^ 

 owing to their much more restricted opportunities for dispersal. 



An adequate investigation into the natural enemies of mosquito larvse in 

 Africa offers a wide field for observation and experiment to anyone who 

 may have the time and opportunity for undert iking the work. 



