FISHES FOR CONTROL OF MOSQUITOES. 15 



clusively masses of filamentous algse, pieces of roots and leaves of 

 vascular plants, and such things as might be picked up in random 

 feeding. In a few small ponds and reservoirs where the shore lines 

 were clean and unobstructed and in which gold fishes only were pres- 

 ent the author found practically no mosquito larvse. This is also 

 frequently the case in fountain basins. In such places there is but 

 little food, and any larvae that appear are probably quickly eaten 

 by the hungry fish. For a number of years the author has kept 

 several rain-water barrels free of mosquito larvae by placing in each 

 one or two small goldfish. If the fish died or was removed, the barrel 

 would be abundantly populated within a few days with wrigglers usu- 

 ally of Culex pipiens^ but occasionally of Aedes triseriatus. With the 

 replacement of the fish the larvae quickly vanished. A number of 

 other fishes were tried, but, while not more efficacious, the goldfish 

 lived longer than any of them, often even surviving the winters when 

 the water in the barrels did not freeze solid. 



These obserA^ations, therefore, fully confirm Smith's statement 

 (1904, p. 107) that— 



the goldfish has its field of usefulness in fountain basins and in small artificial 

 ponds not too much overgrown. In such places where it can reach the very edge 

 of the water it serves very well. 



It should be added that to produce the best results the fish should 

 be fed little or nothing during the mosquito season, as small, hungry 

 fish are many times more useful than overfed and overgrown ones. 

 If multiplication be desired, a portion of the pond should be screened 

 off in the spring with cellar window wire to provide a retreat for the 

 young fry from their cannibalistic elders. The fry should be fed 

 until established. 



MUD MINNOW (Umbra pygmaea), 



Jordan and Evermann give the distribution of this species as low- 

 land streams and swamps coastwise from Long Island to the Neuse 

 River. The closely related TJnibrci limi is found in the Great Lakes 

 basin and northernmost part of the Mississippi Valley drainage. 



In eastern Pennsylvania and New Jersey this interesting little fish 

 is abundant in sluggish creeks and ditches having soft, muddy bot- 

 toms or luxuriant vegetation and in the shallow pools and holes of 

 swamps and bogs where they spend much time buried in the mud or 

 Sphagnum. In the shallow water, often only a few inches deep, of 

 shaded swamps they often abound where no other fishes occur. They 

 were also found commonly in the shallow weedy waters and swamps 

 about the shores of lakes and ponds in Palisades Park. They are 

 exceedingly hardy and will live a long time out of water or buried 

 in the mud of drying pools, a peculiarity which they owe largely to 

 their ability to respire in part by means of the swim bladder, prob- 

 ably assisted by the highly vascular fins, as in Amia. 



No important published account of the food of the eastern mud 

 minnow has been found, but the stomach contents of the closely 

 related Umhra limi have been recorded by Pearse (1918), who re- 

 ported upon a total of 110 stomachs examined and sums up the 

 results of the studies of himself and predecessors as follows (p. 276) : 



The mud minnow is a rather versatile feeder, with the chief constituents of 

 its food, insects (35 per cent), entomostracans (31.3 per cent), and vegetation 



87028°— 22 2 



