18 NORTH AMERICAN ACRIDIID^E. 



clearings in the valleys along the streams and by the summit and 

 ridge " balds." The mountain slopes are generally clothed with a 

 forest cover, either of timber or of a dense, shrubby chaparral. 



The valley clearings lie in the Upper Austral or the Transition 

 zone, according to altitude, and possess a characteristic catnpestrian 

 locust fauna represented by such phytophilous species as Melan- 

 oplus femur-rubmm and M. atla?iis, Stenobothrus curtipennis , Orphulella 

 speciosa, and such geophilous species as Dissosteira Carolina, En- 

 coptolophus sordidus, Chortophaga viridifasciata, Tettix ornahis, T. 

 hancocki, T. arenosus, Paratettix cucullatus, Neotettix bolivari, etc. 

 The " balds " are open spaces of greater or less area situated on 

 the summits or extending along the ridges connecting the summits 

 and are used as pastures for stock. On Roan Mountain and adjacent 

 summits these balds cover hundreds of acres and when not too 

 closely grazed form sedgy lawns of surpassing beauty framed in an 

 unrivaled setting of pink-flowered rhododendrons and dark balsam 

 firs. 



The locust fauna of these balds is for the most part the same as 

 that of the valley clearings campestral species of wide distribution 

 or of boreal character, but with a distinct austral element {Schistocerca 

 americana, Neotettix bolivari) due to the proximity of that zone. 

 Below, and on the ridges, the balds give place suddenly or gradually 

 to deciduous forests. (PI. i, Figs, i, 2; PI. 8, Fig. 1.) 



The forested areas present two distinct kinds of habitat trees 

 and undergrowth inhabited respectively by dendrophile and by 

 thamnophile (tree-loving and thicket-loving) species. The term 

 thamnophilous I shall apply to those dwelling amid tangled, inter- 

 lacing, vegetal undergrowth, be it of woody plants or herbs, since 

 the biological conditions presented by the two are in certain import- 

 ant respects essentially the same, as will be seen later. No strictly 

 arboreal species (such, for instance, as Melanoplus punctidatus) were 

 observed, though very likely occurring. 



Thamnophiixhjs Species. 



All of the woodland species secured were inhabitants of under- 

 growth, whether found among the more open timber or that forming 

 the sole forest-cover of the mountain-sides. The slopes of Grand- 

 father Mountain (see Pi. 1, Fig. 2) are largely clothed with a dense, 

 shrubby chaparral or "laurel bald" made up of laurel, rhododen- 

 dron, Menziesia, Leiophyllum, etc., amid which the apterous Podisma 

 glacialis vatiegala finds a home. Here also lives Melanoplus 



