40 AGRICULTURAL EXPERIMENT STATION. 



Delaware River narrows the banks become higher and the water 

 less salt. As soon as it becomes fresh the migratory forms are 

 unable to breed along its banks. The danger from the west bank 

 of this river m.ay be considered as naught. The banks of the 

 Hudson are high above Manhattan and nowhere along its shores 

 is there any marsh area that is dangerous to New Jersey. Long 

 Island has extensive marsh areas, breeding great numbers of 

 mosquitoes, but Staten Island and Manhattan act as protectors 

 to the New Jersey shore, aside from the fact that active work 

 to control the insects is in progress there. , 



What directs the flight of mosquitoes or determines the direc- 

 tion in which they go? Primarily, the wind. A soft warm 

 south wind will carry them for miles in a single night, and on a 

 quiet night they will fly inland for long distances even against a 

 light breeze. 



A warm west wind carries swarms out to sea, where they 

 perish. Such swarms have been recorded fifteen miles out, and 

 are common five miles out. Nevertheless, though these sea 

 flights are well authenticated, they are not usual, and the chill 

 air at the water's edge seems to invite a settling. This I have 

 observed on Five-Mile Beach, where on a west wind, which car- 

 ried the insects from the marsh area, they seemed checked as soon 

 as they reached the beach, and descended in great numbers to 

 such shelter as was afforded by the scant beach grass and even 

 the wash-up material at the high-tide line. Normal flights are 

 always inland when there is either none or a favoring wind. 

 Seaward flights are forced when high temperature and a stiff 

 west wind work together, as they do but rarely. 



COLOR PREFERENCES. 



It has been asserted that certain colors will attract and others 

 will repel mosquitoes ; but no very definite experiments have been 

 recorded, so far as I know. Dr. Johnson during his work in 

 1902, lined the back of the box in which he kept his mosquitoes 

 under observation, with paper of different colors; but he seemed 

 to find no evidence of any very marked preference. 



In the field I have noticed that black clothing was uniformly 

 more attractive to sollicitans. A man with a black alapaca coat 

 and black hat would have mosquitoes all over the back, while 

 another walking with him, clothed in a gray coat and straw hat, 

 was almost exempt. So, when standing in grass sheltering sol- 

 licitans^ the insects began crawling upon the dark pantaloons in 

 much greater numbers than on gray or light brown. I have no 

 suggestions to make as to the reasons for this preference; but it 



