FLOOD-PLAIN FOREST COMMUNITIES 199 
taken the larvae of the viceroy butterfly (163) and the larvae of the 
cecropia moth (Samia cecropia Linn.). Doubtless forest-edge birds 
nest here also. 
The belt which succeeds the willow is commonly found farther from 
the water and has not been so much studied. It is commonly made up 
of larger willows, river maples, young elms, young ashes, and small 
hawthorns. These are usually much tangled with weeds such as nettles, 
and masses of flood trash and vines. General collecting in such a situ- 
ation along Thorn Creek (August) secured for us the large green stink- 
bug (Nezara hilaris), the spiny assassin-bug (Acholla multispinosa), and 
the broad-winged fulgorid (Ampliscepsa bivittata). On the maples are 
frequently larvae of Symmerista (Fig. 151). Ona small hawthorn were 
a number of larvae of the handmaid moth (Datana). At this stage the 
trees and shrubs become the nesting-places of the yellow warbler and 
American goldfinch, which are probably our most characteristic early 
flood-plain birds. 
In the wet ground of the flood-plain, especially in any small depres- 
sions made by overflows, the crayfish (Cambarus diogenes) is the charac- 
teristic resident. Under driftwood and on the plants of the water 
margin is the slug (Agriolimax campestris), and often also the snails 
(Succinea retusa and avara). 
Such situations are also the chief haunts of the beaver, which cuts 
away the saplings to make its dams. The otter (Lutra canadensis) is 
particularly fond of stream margins. It feeds upon crayfishes, fishes, 
frogs, etc. It has particular powers of traveling long distances and a 
curious habit of sliding down mudbanks and snowbanks for sport (142). 
In winter it progresses on ice by repeatedly running a distance and then 
sliding as far as the momentum will carry the body. The nest is nearly 
always in the stream bank, with the entrance below water. The skunk, 
the mink, and the raccoon are also fond of the stream-margin thicket, the 
latter picking up fish or crayfish if they can be had at night. This animal 
is said to wet its food before devouring it; hence the ‘‘ wachbir”’ of the 
Germans. The skunk likewise devours almost anything that is to be 
had at the water’s edge. 
d) Flood-plain forest association (Station 68; Table XLVIII).—As 
times passes the river cuts lower, the forest develops, and we have 
a dense forest of elm, hawthorn, ash, and basswood, with sometimes 
walnut and butternut, these being partially displaced on the higher 
ground by the oaks. This we may regard as the typical flood-plain 
forest. 
