256 NEW YORK STATE MUSEUM 



which tides rise only occasionally and in which the water is quite 

 brackish. Here the wrigglers have time to develop before the tide 

 again visits the pools, sweeping away their contents. As a rule 

 none are found in pools not reached by tides or in those containing 

 fish^ neither are they found where killifish occur nor in association 

 with fiddler crabs. It will be observed that the breeding places 

 of these two species are confined to limited areas, and conse- 

 quently, while their control may at first sight appear to be a 

 gigantic undertaking, in reality it is largely simplified by these 

 restrictions. 



Other wild species have more or less decided preferences as to 

 breeding grounds, the details of which are given under accounts 

 of the different species. These forms, as a rule, are of minor 

 economic importance, though their habits, as well as those of more 

 annoying mosquitos, should be carefully investigated- 



Natural enemies. Small fish are by far the most important 

 among the natural enemies of mosquitos, and the introduction of 

 suitable forms into fishless waters sometimes affords one of the 

 readiest methods of controlling these pests. Almost all of the 

 small carnivorous fish which inhabit swamp pools and still water 

 will feed on mosquito larvae. This includes nearly all of the 

 minnows, particularly those known as top-minnows. The little 

 sticklebacks are very efficient in this respect. The common little 

 sunfish or " pumpkin seed " is also recommended as a voracious 

 devourer of mosquitos, and it has the advantage of the preceding 

 forms, in that its spined rays protect it from some of the larger 

 fish. The common goldfish has also been reported as an important 

 ally in controlling mosquitos. Tadpoles may eat mosquito larvae, 

 though there appears to be some doubt on this point, and 

 as we have observed larvae in association with tadpoles, they can 

 not be voracious devourers of wrigglers. Mr Koebele of Hawaii 

 has observed a salamander devouring larvae. 



A number of aquatic insects, such as dragon fly larvae, the 

 young of predatory water beetles and various aquatic bugs feed 

 on mosquito larvae and are undoubtedly valuable aids in con- 

 trolling this pest, though hardly forms which could be handled 

 and bred or distributed in the same way as fish. 



