. Bulletin. ly park intown includes this stream is deplorable, as it probably accounts for muchof the malaria. It should be remembered that a park is very often vis-ited for picnics in the evening, when malarial mosquitoes bite. Class VI, Open Drains.—One drain in the north end of town is re-, sponsible for the production of part of the Anopheles mosquitoes inMurphysboro. Class VII, Lakes.—The situation at Carbon Lake, belonging to theCountry Club of Murphysboro, is very similar to that at Thompsons Lakenear Carbondale. Stechers Lake is much more likely to breed Anopheles,especially because of
. Bulletin. ly park intown includes this stream is deplorable, as it probably accounts for muchof the malaria. It should be remembered that a park is very often vis-ited for picnics in the evening, when malarial mosquitoes bite. Class VI, Open Drains.—One drain in the north end of town is re-, sponsible for the production of part of the Anopheles mosquitoes inMurphysboro. Class VII, Lakes.—The situation at Carbon Lake, belonging to theCountry Club of Murphysboro, is very similar to that at Thompsons Lakenear Carbondale. Stechers Lake is much more likely to breed Anopheles,especially because of its grassy edge (Fig. 13). Under the culvert atone end of the lake I was often able to make large collections of Anophelesadults. Class VIII, Temporary Flooded Land.—This type is caused by over-flow of the flats of the Big Muddy River, at the south edge of town. Thehigh water lasts, however, for so short a time that I doubt whether manyof the mosquitoes of Murphysboro can be traced to this source. 323. 324 Class IX, Sink-holes.—The last permanent type is composed of breed-ing-places caused by the sinking of the ground over abandoned coal minesafter the props have rotted down. These sink-holes fill with water, andgrass and cattails spring up around the edges and sometimes in the centerof the pond. Fig. 14 shows one of them. Fig. 15 was taken during thedrouth of midsummer, 1919, when the water was everywhere very many sink-holes the water-line had receded so far from the cattailgrowth that no protection was left for the mosquito larvae. As a conse-quence of this and of the concentration of predaceous insects and ani-mals, there were practically no mosquito larvae in such situations. Thesignificance of this fact will be brought out later under a discussion ofcontrol measures. The accompanying map shows the remarkably largenumber of these sink-holes (eighty in all) just north of Murphysboro. Aconsiderable number are to be found in the vicinity of the Mobile andOhio
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
