NORTH AMERICAN ACRIDIIDJE. 15 



cent or aborted in the soil-inhabiting species. In eastern North 

 America, with few exceptions, the Tettiginae and Oedipodinae are 

 geophilous; the Tryxalinae and Acridiinae are phytophilous. In 

 the West, owing not only to adaptation in habits to an arid environ- 

 ment, but also in part to the close systematic relationship between 

 the Tryxalinae and Oedipodinae, the distinctness of these two groups 

 is less obvious. 



GBOPHII,OUS DIVISION. 



The geophilous species of eastern North America are with one 

 partial exception campestral in distribution, as would naturally be 

 expected. The exception, Spharagemon bolli, is an inhabitant of 

 xerophytic forests as well as of open fields, and in the Southern 

 States is found quite as often in the forest as on the open plain. 



Campestral Geophiles. The campestral geophilous species 

 may be separated into two groups, showing xerophile and hygro- 

 phile tendencies, and represented respectively by the Oedipodinae 

 and the Tettiginae. The former group contains rock-inhabiting, 

 sand-inhabiting, and loam-inhabiting species ; the latter is made up 

 of moisture-loving species, frequenting damp fields, wet meadows, 

 and the shores of streams and ponds. 



Xerophilous Gcophiles. Of saxicolous or rock-frequenting 

 species, Circotettix verruculatus and Spharagemon saxatile of the 

 Northern States are well-known examples. These species are 

 represented in certain parts of the South by Trimerotropis saxatilis, 

 whose habitat is likewise restricted to bare ledges and rocky 

 hills. A colony of this species is located on Stone Mountain, Georgia,* 

 a granite mass which rises 600 feet above the surrounding plain 

 and is almost entirely denuded of soil, whose sun-baked and torrent- 

 washed slopes still provide a scanty existence for a few of these in- 

 sects. (PL 2, Fig. i.) I found it also on the summit of Sand Mountain 

 plateau, near Trenton, Ga., frequenting the bare rock surfaces of 

 the ' 'glades' ' openings in the forest caused by exposure or proximity 

 to the surface of the underlying rock. (PL 2, Fig. 2.) 



Of arenicolous or sand-dwelling species there are several. On 

 the drifting sands of the beach at Cape Henry, Va. , between the 

 shore and the dunes, may be found Trimerotropis maritima, the 

 maritime or sea-side locust, occurring coastwise from southwestern 

 Maine at least as far as North Carolina, and also along the Great 

 L,akes. This species is unknown from inland localities, save as 

 noted. Its congener, T. citrina, however, is found throughout 



*See Senate Doc. No. 84, 57th Congress, pi. xix. 



