HIGH PRAIRIE 289 
situations in Iowa. The green snake (Leopeltis vernalis) is the most 
characteristic reptile. The prairie rattlesnake or Massasauga (Sis- 
trurus catenatus) was formerly common (22). 
Eight nesting birds, all of which are quite familiar to everyone, occur. 
The bobolink nests in a bunch of grass. It feeds upon flea-beetles, 
weevils, ants, bees, wasps, and grasshoppers of the field stratum. The 
meadow lark feeds on parasitic hymenoptera, including the parasite of the 
May-beetle, ground beetles, crickets, grasshoppers, weevils, spiders, etc. 
The dickcissel is similar in habits. The grasshopper sparrow feeds on 
long-horned grasshoppers, flea-beetles, cutworms, and parasitic hymen- 
optera. The vesper sparrow feeds upon moths, flies, ants, beetles, 
grasshopper eggs, etc., and grain and weed seeds. The nighthawk 
builds no nest, flies at twilight, and feeds chiefly upon ants. The 
297 
Fic. 296-—The adult of the wasp which 
is parasitic on the May-beetle grubs 
(Tiphia vulgaris) (after Forbes). 
Fic. 297.—The larva of the same (after 
296 Forbes). 
prairie chicken is the most characteristic bird. Its nest is a simple 
hollow in the grass (Fig. 295). The prairie horned lark builds a nest 
lined with thistledown and feathers. The lark bunting nests in a tuft 
of grass. 
All of the mammals noted in the subterranean stratum should be 
added here, as nearly all of them feed largely in the ground and field 
strata. 
The field-mouse (Microtus ochrogaster Wagner) (21) is a resident of 
the ground stratum. Its nest is a pile of grass fragments on the ground. 
The species feeds chiefly upon grasses and cultivated plants. The 
bison (Bison bison Linn.) is the most characteristic mammal. Thompson- 
Seton says that the bison population of North America was originally 
75,000,000. ‘This animal generally went in clans or families which are 
said to have had characteristics of their own. An old cow was the 
