Proce:e:dings of Fifth Annuai. Mi:eting 39 



"The effect of the foulness of the water in favoring the breed- 

 ing of a certain form of Culex was as marked as in opposing the 

 breeding of Anopheles. To give an idea of their abundance : 

 One small dipper at one dip secured enough pupae to hatch 63 

 mosquities in one night. I confess I dipped for pupae. All that 

 I examined were Ctilex pipiens. The Anopheles were A. 

 quardrimaculaHis and punctipennis, the former mainly. 



''Also at Columbus, a beautiful clear branch comes out of the 

 lake at Forest Lake Park. It runs, say, two miles and is breed- 

 ing Anopheles freely and abundantly in side pools and eddies the 

 whole way. Opposite Hamburger's Mill, it receives the waste 

 from the dyeing vats and all life in the stream disappears for 

 some 500 or 600 feet. Here a large sewer enters and less 

 than feet below its month Culex appear and are found in very 

 large numbers, as we go down. No Anopheles are found below 

 this. The water in which these Culex were breeding was pro- 

 fusely dark wnth dye. 



"I was informed that formalin was used to "set" the dye at 

 this mill. Possibly then, this was the agent which prevented any 

 breeding in the stream above the entrance of the sewer, and being 

 rendered inert by combination with some elements of the sewage, 

 the stream becomies suitable for Culex larvse below the sewer 

 entrance. 



"At Elizabeth City and Fayetteville, N. C, streams receiving 

 dye were free from mosquito larvae of all sorts for long dis- 

 tances, over a male, from the entrance of the dye. These streams 

 were sluggish, however, not quick-flowing like the one at 

 Columbus, and received no- sewage, nor do I know if the same 

 mordant, formalin, was used." 



Mr. William Delaney, Superintendent of the Hudson County 

 Mosquito Extermination Commission, who has had some experi- 

 ence in the matter of sewage pollution, says : 



"Sewage-polluted streams, ponds and even salt water, con- 

 stituite ideal conditions for mosquito breeding, not only because 

 the sewage invariably precludes the presence of killifish, but 

 seemis to attract the female mosquito, particularly the pipiens. 

 We have in our county two tide-water streams, the Cromakill 



