12 
WATERS FROM WHICH COLLECTIONS WERE MADE. 
The nymphs in the State Laboratory collections were de- 
rived from a large variety of waters: from the broad Mississippi 
and Ohio, slow and majestic, but flowing more hurriedly at a 
few points—as at Rock Island and Golconda ; from the bottom- 
land lakes of these streams, muddy and without much vegeta- 
tion ; from the lower course of the Illinois, broad, shallow, slow- 
flowing, with the bottoms more of mud than sand, the shores 
often margined with water vegetation ; from the broad and 
shallow bottom-land lakes along this river, some slightly deeper 
than others, but abounding in floating vegetation,—as Quiver, 
Thompson’s, and Dogfish lakes near Havana,—some shallower 
and swampy, as the great expanse of Flag Lake, and others 
changeable and temporary in character, as Phelps Lake; from 
the smaller affluents of the rivers, usually flowing with an oc- 
casional descent over beds of mud, sand, and gravel ; from the 
small lakes which rest in the ancient glacial hollows to the west 
of Lake Michigan in Illinois and Wisconsin, quite deep in places, 
permanent in character, usually well supplied with aquatic life 
of all kinds ; from the shallow ponds of similar origin scattered 
over the state, of all degrees of permanency ; and, lastly, from 
the rapid flowing rocky streams of Yellowstone Park. These 
waters present a great variety of situations, each with its char- 
acteristic forms, and it is interesting to note how each of these 
situations is occupied by a definite series of nymphs, in accord- 
ance with its particular character. 
NYMPHS INHABITING THE VARIOUS SITUATIONS. 
The nymphs may be roughly grouped in three divisions, 
according to the kind of situation preferred by them. The first 
includes groups having the endophytic habit of oviposition, 
Zygoptera and Arschnide, as well as a few of the more agile 
members of the other families, such as Hagenius among the 
Gomphide, and Mesothemis, Celithemis, and Tramea among the 
Libellulide. The lighter-colored of these clamber among sub- 
merged vegetation, while the dark-colored forms (Calopteryg- 
