THE WATER-CRESS SOWBUG. 15 
are the fresh-water killifishes Fundulus nolo his. i\ diaphanus, and /■'. dispar. 
The first occurs from Michigan to Alabama, Mississippi, and Texas, and is 
rather common in small lowland ponds. The second is found from Maine to 
North Carolina in river mouths, in the Great Lakes, and in practically all of 
the small lakes in the upper Mississippi Valley. The third occurs in smaller 
lakes and ponds from northern Ohio to Illinois and south to Mississippi. 
Specimens of each of these species could be obtained at any one of several 
small lakes in the northern part of Indiana. 
It is probable that some of the catfishes might also be useful in this connec- 
tion, and it is suggested that it might be worth while to try one or more of 
the small species known as "mad Toms," belonging to the genus Schttbeodes. 
One or more species of this genus can be found in almost any small, sluggish 
stream in Pennsylvania, Virginia, and West Virginia. 
The writer believes that carp should prove of value in keeping 
down this cress sowbug, there being one drawback, however, that the 
carp must be watched to see that they do not develop too rapidly 
and that they do not attack the cress or make the water muddy. Cat- 
fish have been tried and found wanting in the case of the water-cress 
leaf-beetle, which will be considered elsewhere (pp. 1G-20). 
