REPORT ON MOSQUITOES. 105 



the Rancocas, Big- and Little Egg Harbors and others, and from 

 these small spring-fed tributaries, many of which never freeze 

 over, let them spread down the streams. I am satisfied that if 

 we go about it right, there will be no trouble in introducing them 

 to such waters ; and in thinking- the matter over in connection 

 with such places as I know of as being suitable, I conclude that 

 spring would be much the best time for the experiment, for the 

 reason that pike and other predaceous fishes collect about the 

 deep holes and spring places in winter, and Ganibusia would have 

 little chance for escape, whereas in the spring they could find 

 protection among the plants and in the shallows where the others 

 ■could not reach them. Another consideration is that in fall we 

 should be submitting a few thousands tO' new and unfavorable 

 ■conditions at the most unlikely time of the year, whereas if we 

 put the same number out in the spring, by fall we can reason- 

 ably expect that there will be tens of thousands, thoroughly 

 familiar with and adapted to the waters in which they began 

 life, and, having known, no' other, there will be no question 

 ■except that of temperature involved. 



"I have seen Gambiisia collected in vast numbers where there 

 was thin ice, at Cape Charles, Va., and I have nO' doubt they 

 passed the winter in those places, where probably the ice was at 

 times two or three inches thick, or even more." 



This would be an ideal species to introduce into ornamental 

 -ponds in which aquatic vegetation forms an important feature. 

 Such ponds having no fish save those which are placed in it would 

 allow this little species to develop unchecked and would abso- 

 lutely prevent all danger of moscjuito breeding. 



Should this work on the moscjuito problem be continued with 

 ;a sufficient appropriation, a careful and systematic attempt to 

 introduce and acclimate this little fish will be made. 



Gregarious Species of Active Habit Inhabiting Fresh Water. 



ABRAMIS CHRYSOLEUCAS. 



Roach, Shiner, Bream. 



" This is one of the most abundant and widely distributed 

 •of our smaller fishes. It is gregarious in habit and very prolific. 

 Though a timid fish, it is very active and one of the most useful 

 for controlling mosquito^ larvae. Schools of them will be con- 

 :stantly moving over certain areas which constitute their ranges. 

 Though they do not penetrate dense masses of plants, they pass 



