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Papers from the Department of Marine Biology. 



At 5 h 30 m on the morning of July 4 the wind was still in the north and 

 continued so during the forenoon. Throughout the afternoon it blew 

 from a few points west of north, again freshening toward night. At 8 

 a. m. the first specimen of what proved to be one of the two important 

 mosquito migrations appeared at the station. This arrival, as may be 

 calculated, was at least 27 hours after the wind had begun blowing 

 from the northeast or north, but no more were noted until between 6 

 and 7 h 30 m p. m., when 3 were taken, indicating that mosquitoes in the 

 vicinity were increasing in number. 



The wind was still blowing moderately from the north at 4 h 30 m a. m. 

 on July 5. That mosquitoes were still about was proved by the cap- 



TABLE 1 . Insects taken at Rebecca Shoal light-station and the conditions of their occurrence. 



