REPORT ON MOSQUITOES. 47 



In fact it is in the pools of low, swampy regions generally that 

 this species finds its favorite habitation. It is the only inland 

 species that has any reputation as a migrant and hence it is of 

 more than local importance. 



There are low places in every woods, and in New Jersey we 

 have considerable areas of low, swampy woodland which are full 

 of water during the winter : in these great numbers oi wrigglers 

 develop in early spring, and in some at intervals throughout the 

 summer. Fortunately the species that breed here are local in 

 their habits, and do not usually get out of the territory where 

 they were born. It is almost safe to count on finding mosquito 

 larvje at any time during the summer in a woodland pool. 



As tO' the salt marshes, there are areas, usually near the edge 

 of the highland, that are rotten or full of holes and irregular 

 depressions, and in every one of these larvae develop when they 

 become filled by either rain or tides. There are also larger 

 depressed areas, reached only by the highest tides, which are 

 refilled chiefly by heavy rains during the summer, and these are 

 among the heaviest of all breeders because of their extent. There 

 is a certain relation between the character of the vegetation and 

 the prevalence of mosquito breeding places, and that has been 

 worked out by Mr. Viereck, whose account may be given. 



Mr. Viereck's Report. 



"At the seashore and inland, high and lowland are characterized by species 

 of grasses and sedges which grow only either in moist or dry places. Thus, 

 inland, while no breeding was discovered in Sphagnum swamps, the worst 

 breeding areas for Ciilcx sylvestris were found in depressions where the sedge 

 of the genus Cyperus grows. This sedge grows chiefly in places where the 

 ground is low and prone to hold rain-waters. 



"At the shore where the highland joins the low sedge marsh there is a zone 

 of (commonly called) salt hay composed of at least three prominent genera 

 of grasses. Nearest the highland and in the less black soil is the three-square 

 grass, Scirpus; this does not hai-bor mosquito-breeding depressions ordinarily, 

 although in some cases, especially near the shore, it grows with Cyperus in 

 low, dangerous places. Beyond the three-square grass, and really a contin- 

 uation of it, is the black grass, Jnncus, which constitutes the largest percentage 

 of salt hay and harbors the worst breeding places of sollicitans and tcenio- 

 rhynchus (as well as cantator). Quite often the standing water causes the 

 grass to drop off, leaving only a stubble behind to stay in the dark brown area, 

 which is a chronic mosquito pond, delivering a brood after every rain which 

 adds enough water to last a week. Where the black grass grows close 

 together breeding is impeded. 



"Between the black grass and the sedge is the joint-grass, Distichlis, which 

 grows by runners and leaves many spaces between the stems, where mosquitoes 

 breed quite freely. In this grass all the salt marsh species proper, and even 

 Anopheles, will readily evade fishes, though it admits fish better than the black 

 grass. 



"Beyond the joint grass the sedge, Spartina, is usually well drained natur- 

 ally. Where this natural drainage is cut off by man or by nature (the latter 



