340 MOSQUITOES OF NORTH AMERICA 



as possible and they went to the round-ups at full speed, and little or nothing was 

 done for nearly five days ; by this time the main body had passed, though plenty 

 remained to make everything uncomfortable for about two weeks. This migra- 

 tion was from east to west and the line was about three miles wide — above and 

 below this there were no mosquitoes. 



" Migration No. 2 occurred in October, 1886. They came from the same 

 marsh before described — this migration confined itself to the Matagorda Bay 

 shore line, reaching inland about half a mile; there were as many mosquitoes 

 in this limit as there were in the three miles of migration No. 1. They clouded 

 the sky, bent down the grass vsdth their weight, and made all driftwood and 

 ground the same color. All stock left the shore and went north outside of the 

 line of marsh. The wind was light and from the south, and did not affect the 

 mosquitoes in their flight, which was westward ; the main flight was low, ten or 

 twelve feet high and always in the same direction. With three other men I rode 

 into the swarm to a large pile of drift and trash and set it on fire, and stood in 

 the smoke for some time watching them. They passed sometime during the 

 third day, leaving very few stragglers behind. By inquiry, I traced both of 

 these swarms from the marsh before described to fifteen or twenty miles west 

 of my ranch, a total distance, air line, of fifty or sixty miles. 



" No. 1 crossed Trupalacios Bay, where it was five miles wide, and Carancahua 

 Bay, where it was one mile wide. No. 2 holding to the shore line, crossed 

 Trupalacios Bay, three miles, Carancahua Bay, at Pass, 300 yards, Keller's Bay, 

 at Pass, half mile. Cox's Bay, one and a half miles, and Port Lavaca Bay, four 

 miles." 



When Dr. John B. Smith began his work in New Jersey nothing exact was 

 known of the breeding habits of the salt-marsh mosquitoes, or of their powers of 

 migration. The fact of their ability to migrate was denied by nearly all ento- 

 mologists. Doctor Smith's early work resulted in the determination of the life- 

 history of Aedes sollicitans, and his later work, that in 1903-4, resulted in a 

 complete demonstration of the migratory habits of A. sollicitans, A. cantator and 

 A. tceniorliynchus. He was led to investigate the matter carefully on account 

 of the fact that anti-mosquito operations carried on in certain New Jersey towns, 

 on the theory that the entire mosquito supply was bred locally, were unsuccessful ; 

 furthermore, the salt-marsh mosquitoes were found far inland and in numbers 

 too large to have been carried by trains ; and lastly, experiments indicated that 

 they would not breed in fresh water. The controlling argument was the pres- 

 ence in overwhelming numbers of adult salt-marsh mosquitoes where no trace 

 of their larvae could be found. Doctor Smith had previously watched sollicitans 

 carefully on many occasions and had found that it flies quite readily against even 

 a brisk wind, and makes good progress. He placed himself several times in an 

 alley in the direct line of the wind and watched the mosquitoes come sailing 

 against it without apparent effort. He had driven, as have many of us, over 

 infested roads at quite a rapid pace, and had found that the mosquitoes hovering 

 over the horse and about the carriage had no difficulty in keeping up. He had 

 been in a steam launch which was followed by a mosquito swarm for more than 

 five miles across an open stretch of water. 



In order to understand the sudden appearance of great numbers of mosquitoes 

 on the salt marshes and their subsequent migration a knowledge of the breeding 



