246 PESTS AND NUISANCES 



for about two weeks. The grade of kerosene known as " light fuel oil " 

 is best. 



Any kerosene will kill aquatic plants, if sprayed on them. It 

 should be poured on surface of water in cultivated ponds and spread 

 with a broom or mop. It should be applied oftener than once in two 

 weeks in such cases, and in much less quantity. One-fourth as much 

 twice as often will probably be equally effective. 



It is best not to use kerosene at all on ornamental ponds ; it is un- 

 sightly ; it smells badly ; it kills all larvce that require air derived from 

 the surface, including those of many of the higher diptera which as adults 

 are useful flower pollinators ; it endangers the plants even when most 

 carefully applied, to say nothing of smearing them. 



Fishes available for destruction of mosquito larvce (Needham). 



1. Goldfish eat eggs by preference, also the larvae. They thrive 

 in any warm pool, or even in cisterns with scant light ; eat prepared 

 foods, so can be readily supplied with supplemental food if necessary. 

 They are easily obtained in the market, and are ornamental. Must 

 be taken indoors for winter. 



2. Top minnows are natural enemies of mosquitoes in native water. 

 They are hardy and long-lived ; but they are not on the market, and 

 have to be sought with a seine. Not especially ormrmental. 



3. Sunfish are fond of mosquito larva?. They do well only in 

 midst of aquatic growth; require much food, and insect food is pre- 

 ferred. Ornamental. 



4. Sticklebacks are most voracious mosquito enemies, and are also 

 worthy of cultivation for their remarkable nest-building habits. Rather 

 particular as to conditions, but in proper pools they are hardy. 



All these fishes require room in which pasturage may grow. A pair 

 of the smallest of them would probably find scant natural food in a 

 square rod of water area. 



Hibernating mosquitoes. 



Some mosquitoes hibernate in cellars, and from them the breeding 

 starts in spring. Cellars may be fumigated with powdered Datura Stra- 

 monium (Jimpson weed), or with culicide (culex is the generic name of 

 the greater number of mosquitoes). In either case, according to J. B. 

 Smith, the cellar to be fumigated should be as tightly closed as possible, 



