FISH CONTROL 



179 



The ease with which F. heteroclitus may be artificially ferti- 

 lized and the hardihood of the young embryos make the stocking 

 of pools and streams with this fish an easy and satisfactory method 

 of mosquito control. 



THE STRIPED KILLIFISH {Fundulus majalis) 

 This killifish, which may be distinguished from F. heteroclitus 

 by its color, the fact that its tail-fin is not so convex and that 

 its average length is an inch or more greater, is also considered 

 as having some value in anti-mosquito work. 





£9ff 





Fig. 123. — Fundulus diaphanous; male above and female below. (From Jordan 

 and Evermann, Bull. 47. U. S. National Museum.) 



Males of this species show vertical markings on the sides, 

 while the females have more or less horizontal markings on the 



sides. 



This fish enters the marshes with the tide and goes out with it. 

 Should it get cut off from the ocean, it will, according to Mast, 1 

 travel overland toward the sea by flopping itself along. Mast 

 also shows that this fish seems to keep its sense of direction 

 while traveling overland, which he attributes to internal factors. 



THE FRESH-WATER KILLY (Fundulus diaphanous) 



This species differs from both of the preceding in that its 

 tail-fin is not rounded at all, but is squarely cut off. The females" 



1 The Behavior of Fundulus with Especial Reference to Overland Escape 

 from Tide-pools, Journal of Animal Behavior, 1915. 





