l8 FURTHER RESEARCHES ON NORTH AMERICAN ACRIDIID.. 



The north side of these ranges is much moister, more densely 

 shaded, its plant covering more boreal, and altogether presents a very 

 different environment from the southern side. At a station of this 

 character on the north side of Magazine Mountain, almost in the 

 shadow of the summit escarpment, in an herbaceous thicket composed 

 largely of Urtica gradlis, Polygonum virginianum, Amphicarpoea 

 monoica, Eupatorium ageratoides and Solidago sp. was found Melanoplus 

 gradlis, whose delicate olive coloration exactly matched the back- 

 ground of its haunts, so widely at variance with that of the opposite 

 side of the mountain summit. Continued search in other localities of 

 this character would probably reveal additional species characteristic 

 of this type of habitat. 



The higher summits of the mountains rise to an elevation of but 

 2,400 to 2,600 feet, Magazine or Blue Mountain reaching 2,800 at one 

 point and being the highest point of land between the Appalachian 

 and the Rocky Mountains. This elevation is not sufficient to provide 

 true boreal conditions, but does modify the temperature so that cer- 

 tain species, abundant at the north, and forced southward during the 

 glacial epoch, have been enabled to exist in this latitude till the 

 present time. Such are Tettix hancocki, Chloealtis conspersa, and Mela- 

 noplus fasciatus (= baconi of McNeill). 



The two summits of the Ouachitas visited, Rich Mountain and 

 Magazine Mountain, differ very noticeably in the relative abundance 

 of the two common campestrian species Melanoplus atlanis andfemur- 

 rubrum, which are plentiful on the first, scarce on the second. This 

 difference is no doubt due primarily to the fact that the summit of 

 Rich Mountain was for many years the site of prosperous farms, now 

 abandoned and rapidly reverting to original conditions (pi. 3, fig. i). 

 The summit of Magazine Mountain, on the other hand, has been much 

 less disturbed by cultivation, and the forest covers a great part of it. 

 The flat top of this mountain is bounded by an almost continuous 

 escarpment, the rock being commonly exposed at the level margin 

 and forming an ideal habitat for Trimerotropis saxatilis (pi. 4, fig. i). 

 At the extreme west end of the summit, where the roadway climbs it, 

 and where a small area has been recently cleared of trees, an inter- 

 esting assemblage of species was found among the golden-rod, blue- 

 berries, grass, and shrubby sprouts that have sprung up (pi. 4, fig. 2). 

 Here were taken Trimerotropis saxatilis, Hesperotettix pratensis, Bo'op- 

 edon auriventris, Paratylotropidia brunneri, Melanoplus scudderi, M. 

 obovatipennis , Hippiscus phoenicopterus , Spharagemon bolli, Schistocerca 

 rubiginosa, Orphulella pelidna, and several others, some of them in 

 numbers. 



