INFLUENCE OF ENVIRONMENT 261 



The author (10) records tracing both A. cantator and A. sollicitans 

 far into the territory lying back of the salt marsh from which they 

 come. He says that in New Jersey twenty-five-mile migrations of these 

 species are common and that thirty-five to forty-mile migrations occur 

 when broods are large and weather conditions favorable. He makes the 

 point that A. cantator does not go as far as A. sollicitans and states 

 that the difference may be due to the cooler weather prevailing when 

 A. cantator takes wing. 



Dr. D. P. Curry, Assistant Chief Health Officer of the Panama Canal 

 Zone, records the arrival of a brood of A. sollicitans aboard the SS 

 Cristobal on September 11, 1937, while the ship was enroute to New 

 York from Cristobal and Colon. When this brood appeared the ship 

 was located off Cape Henry, 110 miles from shore. The brood was a 

 large swarm of mosquitoes sufficient to render the passengers uncom- 

 fortable. The mosquitoes arrived suddenly. A. sollicitans is not pro- 

 duced in swarms in Colon and Cristobal or anywhere in West Indies 

 and only to a limited extent on the southern coast of the United States. 

 It is therefore evident that this brood winged its way over the ocean 

 from the American shore to the ship 110 miles away. 



Russell (see Table X) has shown a flight of two miles for An. an- 

 nulipalpis. LePrince and Orenstein (17) have cited incontrovertible 

 evidence to show a flight of 6,250 feet by An. tarsimaculata and An. al- 

 himanus (the latter a very important carrier of malaria). 



The author (10) has collected evidence to show movement of C. 

 pipiens from an area of very intense breeding to a point fully 2.5 

 miles away. 



Smith (23) records the fact that A. vexans may migrate as far as 

 five miles. The author (10) has published evidence that this species 

 sometimes moves as much as ten miles and that this movement is in- 

 fluenced by topography. Clarke (5) has shown movement of this species 

 of a little more than fifteen miles and in plains country that this move- 

 ment is radial in character. Matheson (18) records movements of M. 

 pBrturhans of at least fifteen miles. 



Thus the recorded facts seem to show that certain salt marsh forms 

 readily move thirty-five to forty miles and show an extreme distance 

 of 110 miles, that malarial mosquitoes move from one to two miles, that 

 the fresh water swamp mosquitoes move ten to fifteen miles, that the 

 principal house mosquito moves at least 2.5 miles, and that distance of 

 movement is probably correlated with density of emerging brood. 



The woodland pool mosquito group has thus far shown no long 

 flights, but may show something of the sort with further study. 



