WATER MARGIN COMMUNITIES 181 
close to the water. The tiger-beetle of the Lake Michigan shore is dis- 
placed by that of another (Cicindela repanda) which is less active. With 
these is the hooded grouse locust (Paratettix cucullatus) (Fig. 137) (40, 
p- 419). The small semiaquatic snail (Lymnaea modicella) is frequently 
present in numbers. 
The nests of the spotted sandpiper (108, 141) and the yellowlegs are 
found here, and the birds no doubt feed upon the invertebrates present 
on the margins of the ponds and of the shallow water. 
c) Association of sedge margins of ponds and small lakes (Stations 
32-34; Tables XL, XLI).—As time goes on, the sandy margin is 
captured by sedges which are scattered at first, so that the animals just 
discussed continue for a time among them (Figs. 138, 139). Finally, 
however, the ground becomes sodded over 
with sedges and a low prairie animal commu- 
nity comes in, and the bare ground animals 
disappear. In the case of ponds which are 
to develop into forest this stage is found 
only along the young ones. The sedges are 
soon displaced by shrubs and the sedge 
communities give way to shrub. 
d) Associations of shrub margins of ponds 
and small lakes (Fig. 140) (Stations 34, 37, 
44; Tables XLI, XLII).—Mr. Allee has 
verified my observations to the effect that 
the aquatic part of this formation is almost 
entirely barren; however, in summer we get 
the short-winged and armed grouse locust (Tettigidea armata Morse, 
and parvipennis Harr.) (40) and the slimy salamander (Plethodon 
glutinosus) (152) (Fig. 141). Of the birds associated with the water 
we have here the wood-duck and the green heron. 
Fic. 137.—Hooded grouse 
locust (Paratettix cucullatus) 
(after Lugger). 
4. MARGINS OF RIVERS 
(Station 29) 
Here the sandy margin is similar to that of the ponds and lake. 
Along the Fox River we find the mole cricket (40) which burrows into 
the sand. Mud margins are rather barren except for occasional beetles. 
The margins of rivers which are grassy or marshy are like those of ponds 
and lakes. The margins of the Calumet and lower Deep rivers are 
covered with marsh plants and saturated with water in spring. They 
are the nesting-places of the long-billed marsh wren (Figs. 142, 143) and 
many other marsh birds (108, 153). 
