Clirysochiis aiirahis .1 /■'ocyiiiiiii caiiiiahiiiiiin 



ricctrodcra scalator 



MctacJiroiua ivigiistiihiiii 



MctacJiroma parallel it iii 



Li)ia iiitcrrupta 



I. ilia scripta 



Populiis and Salix spp. 



Though Populus and Salix are not in reality plants of the bunch- 

 grass association, they are frequently found in the sand area. 



Of the herbicolous plant-feeders, the grasshoppers (Acridiidae) 

 are by far the most abundant and the most conspicuous. It is prob- 

 able that the quantity of plant material eaten by them would be at 

 least one-fourth as great as that eaten by all the other animals in 

 the association. The grasshoppers have numerous enemies, and con- 

 stitute a large part of the food supply of the predaceous and parasitic 

 members of the association. They are doniiiianl animals. 



Terricolous Plant-feeders. — The ground stratum consists in real- 

 ity of two more or less well-defined divisions which may be called 

 siiface and subsurface The cotton-tail rabbit is a surface animal. 

 The sub-surface group includes animals in surface burrows, as ant- 

 lions, and animals found under cover of some kind, as leaves, boards, 

 stones, ov at the base of plants. Xysticus gulosus, Termes, Lacon 

 reclaii(/iilaris, and many other insects are typically found at the sur- 

 face, under cover. It is seen that distribution of the animals varies 

 horizontally as well as vertically, the various layers not being homo- 

 geneous throughout. Though in some associations the sub-surface 

 habitat is continuous, as the habitat furnished by the leaf-mold of a 

 forest floor, in the bunch-grass it is of limited extent and much scat- 

 tered, boards and rocks being accidental in sand prairie. Plant- 

 eaters, predaceous animals, parasites, and scavengers are all repre- 

 sented in the surface and sub-surface habitats, predaceous animals 

 being perhaps most conspicuous. The surface phytophagous animals 

 are prol)al)ly not exclusively ground-feeders. 



(i) Surface phyto[)hagous animals 



"^Ageneotettix deoniiii Coliiuis liryiuiaiiiis I'iryiiiiaiiits 



*Hippiscus spp. Zcnaidura macroiira caroliiiciisis 



^Spharageiiion ^cyoiiiiiu/iaiiinu Otocoris alpcstris praticola 



*Mesfobre(jiiia flioiiiasi *Stuniclla neglecta 



Ps'uiidia feiiestralis *Poococtes grainlneus graininciis 



"^Melanophis angusiipcnnis ^-Chondestes grainmacus graiii- 



iiiacus 



