22 FURTHER RESEARCHES ON NORTH AMERICAN ACRIDIIM. 



Patches of weeds (A mbrosia, Euphorbia, Grmdelia,etc., pi. 5, fig. 2, 

 middle distance; pi. 6, fig. 2, foreground) give shelter or sustenance 

 to Aeoloplus, Melanoplus differentialis , and several other species of this 

 genus and of Schistocerca and Hesperotettix ; while the tall sunflowers 

 of gulches and waste corners form favorite perches for the huge and 

 sluggish lubber or buffalo hopper (Brachystola magnd). 



The Wichita mountains form a considerable tract of rugged country 

 of low elevation near the center of southern Oklahoma and represent 

 the summits of an ancient mountain range formerly of much greater 

 elevation and continued eastward in the Arbuckle and other ranges in 

 Indian Territory and western Arkansas, but now almost submerged 

 beneath the accumulation of flood-wash material forming the prairie- 

 plains at their base. Some are of rounded contour with grassy slopes, 

 others present summits of bare, sun-scorched crags and boulders 

 nearly devoid of vegetation and jutting suddenly upward from the 

 level plain (pi. 7, fig. i). Tracts of open forest clothe many of the 

 higher slopes and fringe the streams of the district, oaks predominat- 

 ing, with numerous cedars on the higher summits (pis. 7, 8, 9). Two 

 peaks, Mounts Scott and Sheridan, rise to an elevation of approxi- 

 mately 2,500 feet, at a distance of 10 or 12 miles in a northerly direc- 

 tion from Cache, from which point, or from Fort Sill, they may be 

 readily reached by team. A day was spent, from Cache as the point 

 of departure, in a trip to Mount Sheridan. 



As might be expected, owing to its low elevation and limited 

 area, the locust fauna of the summit is essentially the same as that of 

 the plains at its base, but scantier, the only variations found corre- 

 sponding exactly with the difference in character of the habitats repre- 

 sented. On the bare rock slopes and weathered boulders of the summit 

 of Mount Sheridan (pi. 9, fig. i) and of the outlying rocky spur near 

 Mountain Park (pi. 7) were found relict colonies of Trime.rotropis 

 saxatilis (p. 40); in the woods about Mount Sheridan and along the 

 stream at Cache are found the forest-loving species Spharagemon bolli, 

 Melanoplus keeleri, robustus, and scudderi. Other species taken in the 

 bunch-grass of the mountain-top were Mermiria bivittata and neo- 

 mexicana, Syrbula admirabilis , Orphulella decora, Hippiscus rugosus, 

 Melanoplus bispinosus and packardii, all species that are common on 

 the plains. As a whole, insect life of all kinds was very scarce upon 

 the summit. 



Another capture of interest in this locality was that of a repre- 

 sentative of Telmatettix, a genus distributed widely in Mexico and the 

 far west, which was taken on the stony fragments in the stream-bed at 

 the foot of the northern talus-slope of Mount Sheridan. 



