PRACTICAL USE OF NATURAL ENEMIES OF MOSQUITOES. 63 



itself in the adult condition is a voracious biter and is a potential 

 carrier of disease, so that to breed it for predaceous purposes is 

 hardly to be considered; in other words, the remedy might prove 

 worse than the disease. However, Dr. Oswaldo Goncalves Cruz, 

 director-general of the board of health in Rio de Janeiro, told the 

 writer in November, 1907, while on a visit to Washington, that 

 Lutzia higotii is used in Rio practically to destroy the larvae of the 

 yellow-fever mosquito. The Lutzia larvae are exclusively carnivo- 

 rous, and this species is introduced in regions where the mosquito 

 abounds, and its larvae destroy the other larvae as efficaciously as do 

 fish. 



For a long time fish have been used practically on a small scale. 

 For example, it was stated a number of years ago in Insect Life that 

 mosquitoes were at one time very abundant on the Riviera in south 

 Europe, and that one of the English residents found that they bred 

 abundantly in water tanks, and introduced carp into the tanks for 

 the purpose of destroying the larvae. It is said that this was done 

 with success, but it is rather certain that the fish must have been 

 some other form than carp. It is probable that the fish in question 

 was the common goldfish {Carassius auratus). 



In the southern United States for many years intelligent persons 

 here and there have introduced fish into water tanks for this purpose. 

 Mr. E. A. Schwarz found in 1895 that at Beeville, Tex., a little fish 

 was used. The fish was called a perch, but its exact specific character 

 is not known. Prior to 1900, Mr. F. W. Urich, of Trinidad, wrote the 

 Bureau of Entomology that there is a little cyprinoid, common in that 

 island, which answers admirably for the purpose. In a letter to the 

 Bureau of Entomology Mr. J. B. Fort, of Athens, Ga., writes that 

 about 1854 his father. Dr. Tomlinson Fort, living at Milledgeville, 

 Ga., found that mosquitoes were breeding extensively in a cistern 

 owned by certain livery-stable keepers. They refused to use oil upon 

 their cistern, and Mr. Fort was instructed by his father to catch 

 some small fish from a creek near by and place them in the cistern. 

 About a dozen or more small fish were so placed, and in a day or so all 

 of the larvae were destroyed. This instance is mentioned as indica- 

 ting the early use of fish on a small scale in cisterns. 



In ''Mosquitoes" (1901) the writer recommended the practical use 

 of sticklebacks, top-minnows (Gamhusia affinis and Fundulus notatus) , 

 and the common sunfish or pumpkinseed, and these fish, especially 

 the top-minnows and the sunfish, were used with success in a number 

 of instances in small ponds. An instance has been described in a 

 letter to the Bureau of Entomology by C. T. Anderson, of Anderson, 

 Washington County, Fla., who wrote that he had a spring on his place 

 that swarmed with mosquito larvae in the summertime. He got 

 about a dozen top-minnows and put them into the spring without 



