March, I9I3-] GrOSSBECK : MOSQUITOES AND ENVIRONMENT. 57 



addicted to a clean water environment. Resfnans, however, with one 

 or two other species is not uncommonly found in the same situations 

 as pipiens. 



The salt marsh is an environment to which five species in this 

 region confine themselves for breeding purposes. The mosquito fauna 

 of the salt marsh is distinctive, none of the species living on it in the 

 larval stage breeding anywhere else. Culex sollicitans is always the 

 most abundant and is found in practically all the temporary pools un- 

 inhabited by fish. With it is found Culex tceniorhynchus and Culex 

 cantator. The latter prefers those areas which merge into the fresh 

 water marsh, such, for instance, as occur along rivers, rather than 

 those which border the bays ; but never is it found in strictly fresh 

 water swamps. Culex salinarius, a not remote ally of the house mos- 

 quito, is the fourth species found on the salt marsh, and Anopheles 

 crucians the fifth. The first three of these five species are migrants 

 and are frequently found for many miles inland and away from the 

 salt marsh, but never have the larvae been found in fresh water pools. 

 That the salt water is not a prerequisite for the development of the 

 larvse is evidenced by the fact that eggs of these species will hatch 

 and the resulting larvae mature in water that is absolutely fresh. 



Another environment is the temporary pools of open fields, the 

 more shallow open swamps which usually consist of a series of tem- 

 porary pools more or less connected, and the shallow edges of 

 ponds subject to the rise and fall of the water. These situations 

 are all very similar when looked at from the mosquito-breeding 

 standpoint, and contain practically the same species of mosqui- 

 toes. Thus Culex sylvestris is found in all of these places, though 

 in smaller and more scattered numbers in the ponds, due prob- 

 ably to the greater struggle for existence. Culex trivittatus, C. 

 jamaicensis and C. discolor are found in the same places, but to a less 

 extent at the edge of the ponds. Psorophora ciliata occurs usually 

 only in clear pools of the most transient character and two species of 

 Anopheles, namely, punctipennis and maculipennis usually occur in 

 such of these places as are to some extent overgrown with vegetation. 

 The first of these two is occasionally found in pools with a clayey 

 bottom and no vegetation, and in places inhabited by Culex pipiens 

 but these are exceptions not often found. Maculipennis is more 

 given to inhabiting pools and swampy regions at the edges of the 

 woodland, or more rarely in the woodland itself. 



