762 



SCIENCE. 



[N. S. Vol. XVIII. No. 467. 



absolutely necessary that the point should be 

 positively determined, since no comprehensive 

 plan can be formulated without considering 

 how such migratory forms should be dealt 

 with and what authority should have control. 



During the season of 1902 I worked out the 

 life cycle of Culex sollicitans, and satisfied 

 myself that it was a true migrant. I found 

 associated with it three other species, breed- 

 ing under similar conditions, whose status I 

 could not altogether fix. These were C. nigri- 

 tulus, G. tceniorhynclius and one which I made 

 certain was different from described species; 

 but which was then determined by authorities 

 to be a form of C. sylvestris. Further study 

 proved my contention as to this species to be 

 correct, and it has been recently named C. 

 cantator by Mr. Coquillett. All these breed 

 on the salt marshes and, as a rule, on the 

 marshes only, though the water may be salt 

 or fresh. 0. nigritulus I have never found 

 far away from the edge of the marsh in the 

 adult condition. C. tceniorhynchus never flies 

 very far nor in any considerable numbers. 

 C. cantator and sollicitans have equal powers 

 of flight and either may be dominant on the 

 marsh at a given period, or both may be 

 equally abundant. 



Investigations made in 1903 indicate that 

 0. cantator gets an earlier start and may fly 

 long before sollicitans appears in large broods. 

 Further, it is more northern in its range and, 

 while it equals or exceeds sollicitans on the 

 Raritan and Newark marshes, it is hardly 

 noticeable from Barnegat Bay southward. 



C. cantator is a stout, hairy yellowish- 

 brown mosquito with obscurely banded legs; 

 very difi^erent from the bright contrasts found 

 in sollicitans. 



To determine the question of migration and 

 breeding areas positively, one observer was 

 located at Cape May from the beginning of 

 June to the end of September, with instruc- 

 tions to watch C. sollicitans day by day and, 

 if it bred anywhere on the peninsula, to find 

 the breeding places. Mr. Henry L. Viereck, 

 who made these observations, reports positively 

 that, while the adult occurred throughout the 

 territory assigned to him, it bred only on the 

 salt marshes or at their edge. Furthermore, 



he observed directlj' that, shortly after a brood 

 emerged on the marshes, there would come a 

 sudden decrease in the numbers of adults and 

 a corresponding increase at points inland. In 

 all his collectings not a sollicitans larva was 

 found in the fresh-water swamp area of the 

 peninsula ! 



Six other collectors were regularly in the 

 field during the breeding season — not inter- 

 mittently, but daily, and the result was that 

 thirty-three species of mosquitoes were col- 

 lected. And of these, thirty-one were actually 

 bred from larvae during the summer! Much 

 of this collecting was done in the regions 

 dominated by sollicitans and cantator, yet 

 neither was found at any time in the larval 

 stage away from the salt marshes or their edge. 



Personally I watched the emergence of an 

 early brood of cantator on the Newark mea- 

 dows before there was a mosquito in the city, 

 and when the surroundings on the hillside had 

 been thoroughly surveyed and no similar larvse 

 discovered. These adults were watched from 

 day to day as they spread inland until the 

 city swarmed with them and they invaded the 

 surrounding country in every direction. G. 

 sollicitans did not at any time in 1903 dom- 

 inate the Newark meadows as it did in 1902, 

 and cantator was not generally recognized at 

 first as a salt-marsh species. 



At the mouth of the Raritan River the 

 marshes near Perth and South Amboy were 

 kept under close observation throughout June, 

 and toward the end of that month conditions 

 favored the development of an immense brood 

 of mixed sollicitans, cantator and tceniorhyn- 

 chus. Meanwhile the course of the Raritan 

 had been followed up to Bound Brook and 

 the territory around New Brunswick and 

 Metuchen had been explored for miles without 

 finding similar larvae. July 1, the Amboy 

 meadows were alive with adults, and during 

 the night of July 2 to 3 the advance guard 

 reached New Brunswick. The main body 

 came during the two or three next following 

 nights and extended up the Raritan valley. 

 Another body followed a depression toward 

 Metuchen and concentrated on Dunellen, 

 where no chance for breeding such mosquito 

 hordes exists. 



