TOP MINNOWS 405 



Hygiene, September 15, 1909, pages 271-272. A careful search was made in 

 the marshes to the north and south of Larnaca, but no breeding-places of Anoph- 

 eles mosquitoes were found, and subsequent search showed that the malarial 

 mosquitoes were breeding in the tanks and wells of private houses. Here kero- 

 sene could not be used, and the use of goldfish was advised. Wherever the advice 

 was followed, the results were perfect. One well described by Williamson was 

 about twenty feet deep and had a wide mouth. This well contained Anopheles 

 larvae in enormous numbers, and of five persons living within its immediate 

 neighborhood four became infected with malaria. This well, not being in use, 

 was filled in, but a large tank which was near it was stocked with goldfish and 

 all Anopheles larvae were destroyed by them. 



Sir Eubert Boyce, in his recently published volume " Mosquito or Man ? " 

 (London, John Murray, 1909), calls attention to the fact that in Barbados, 

 where it is a very common practice amongst the natives to keep one or two small 

 goldfish in the drinking-water barrel, the native residents, in reply to the ques- 

 tion as to why the fish were put in the barrels, stated that they had been taught 

 to do so by their parents or grandparents for the reason that if a maliciously 

 inclined neighbor should poison the water the goldfish would die, turn up and 

 float on the surface, thus indicating that the water was dangerous. 



An excellent discussion of the relative value of the different small fish of the 

 Atlantic coast-region for practical use against mosquito larvse has been pub- 

 lished by Mr. William P. Seal, a naturalist of many years experience in handling 

 fishes, and the following paragraphs, taken from this article, may be considered 

 as authoritative. (See Scientific American Supplement, May 30, 1908, vol. 65, 

 no. 1692, pp. 351-352.) 



" As a destroyer of Anopheles the writer has for several years advocated the 

 use of Gambusia affinis, a small viviparous species of fish to be found on the 

 South Atlantic coast from Delaware to Florida. A still smaller species of 

 another genus, Heterandria formosa, is generally to be found with Gambusia 

 and is of the same general character. The females are about one inch long, and 

 the males three-quarters of an inch. Both of these species are known as top- 

 minnows, from their habit of being constantly at the surface, and feeding there. 

 The conformation of mouth, the lower jaw projecting, is evidence of their top- 

 feeding habits. Both of these species are to be found in great numbers in the 

 South in the shallow margins of lakes, ponds, and streams in the tidewater 

 regions wherever there is marginal grass or aquatic and semi-aquatic vegetation. 

 They are also to be found in shallow ditches and surface drains where the water 

 is not foul, even where it is but the fraction of an inch deep. In fact, if any fishes 

 will find their way to the remotest possible breeding places of the mosquito, it 

 will be these. And they are the only ones, so far as the writer's observation goes, 

 that can be considered useful as destroyers of Anopheles larvae. 



" Gambusia is found in the Ohio Valley as far north as southern Illinois, 

 where the winter climate must be at least as severe as that of the coast of New 

 York and New Jersey. 



" Dr. Hugh M. Smith, Deputy U. S. Fish Commissioner, informed the writer 

 that he had examined the stomachs of several hundreds of Gambusia in the 

 Chesapeake Bay and Albemarle Sound waters, and had found the contents to be 

 principally mosquito larvse. . . . 



