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bark and small sticks which gather like a scum on the water) to be 

 stranded ashore, a condition imfavourable to the larvae, as floatage 

 plays an important role in protecting larvae. The change of level of 

 this pond is an efficient deterrent to mosquito production as much 

 floatage is stranded and the larvae are rendered more accessible to 

 fish. The effect of winds is to lessen breeding and it is greater in the 

 case of the pond than it can be in a river or stream. In conclusion, 

 it may be said that the pond has enormously diminished the area of 

 breeding places of Anopheles, both adjoining the river and in the valleys 

 of the creeks. This statement however only refers to the condition 

 of the pond in the summer of 1914. 



Le Prince (J. A. A.). Impounded Waters : A study of such waters 

 on the Coosa River in Shelby, Chilton, Talladega, and Coosa 

 counties, Ala., to determine the extent to which they affect the 

 production of Anophelines, and of the particular conditions which 

 increase or decrease their propagation. — Public Health Reports, 

 Washington, D.C., xxx, no. 7, 12th February 1915, pp. 473-481, 

 2 sketch-maps. 

 During October and November 1914, a survey was made of the 

 water of the Coosa River, impounded by a dam about 14 miles from 

 Clanton, Chilton County, Ala. The impounded water extends for 

 about 20 miles upstream from the dam. Pine trees are very numerous 

 in the area examined, many standing close to the banks, while some 

 were allowed to remain in the areas that were flooded. The needles 

 of the pine trees that fell into the lake or were carried into it by streams, 

 collected into large or small groups and afforded most excellent 

 protection for Anopheles larvae. They constitute the most important 

 factor for the production of these larvae in the lake, as well as in some 

 of the streams beyond and outside the influence of the impounded 

 waters, and over 90 per cent, of the Anopheles larvae and pupae 

 collected in the lake were taken by dipping among collections of pine 

 needles, where they were found in all stages of development . Frequently 

 where pine needles were absent. Anopheles larvae were either very 

 scarce or absent ; where pine needles were present in collections of 

 debris, the larvae were almost invariably to be foimd alongside of a 

 floating pine needle, rather than against a piece of bark, twig or 

 other debris. The relative importance of places where larvae were 

 found in the lake was in the following order : — Groups of pine needles 

 (when not too closely compacted) ; debris — consisting of bark, leaves, 

 and twigs ; long grass lying on the water surface ; dead leaves of trees 

 floating on the surface (present from September to November) ; 

 logs, branches, stumps, etc. This inspection was made during the 

 late autumn, so that conditions at other times make further examination 

 necessary. A total of 1,271 adult mosquitos emerged from material 

 collected. Of these, 1,152 were Anopheles punctipennis, 18 Ciilex. 

 (species not yet determined), and 101 A. quadrimaculatus. The adults 

 of the latter species found in natural hiding places were too small in 

 number to have any practical bearing on the spread of malaria in 

 the surrounding country. The scarcity of small larvae-destroying 

 fish in the lake in 1914, is the reason why many larvae and pupae of 

 A. punctipennis were present at some of the inlets examined. 



