444 PROCEEDINGS OF THE ACADEMY OF [June, 



The remaining subdivisions I am disposed to consider as tension 

 zones in which there is more or less interminghng, overlapping, or 

 interdigitation of the faunas from the surrounding primary districts. 

 The faunistic status of the Highlands is still somewhat doubtful, 

 owing to the lack of sufficient data, but the data at hand indicate 

 that its only distinctive feature is the overlapping of Piedmont and 

 Appalachian types. The Middle District does not have a single 

 distinctive species of Orthoptera,^ but represents a zone in which 

 there is an intermingling of characteristic Piedmont, Pine Barren, 

 and Coastal types. The Cape May District has some claim to be 

 regarded as a primary district, since two or three Orthoptera have 

 been taken there which have not as yet been recorded elsewhere, but 

 which future collecting may possibly prove to extend into the Middle 

 and Coastal Districts. The Maritime District is very clearly charac- 

 terized from all the other districts, but I think it preferable to regard 

 it as an ecological subdivision of the Coastal District rather than a 

 separate faunistic region. 



I. The Appalachian District. 



The Appalachian District includes the region between the Blue 

 Ridge and the Alleghany escarpment, thus taking in all of central 

 and northeastern Pennsylvania and extreme northwestern New 

 Jersey. Topographically, the greater part of the region consists, as 

 is well known, of a succession of roughly parallel ridges and inter- 

 vening valleys. In northeastern Pennsylvania these merge into a 

 high plateau, the Pocono Plateau. The underlying rocks are all 

 thoroughly indurated sedimentaries, which typically are charac- 

 terized by steep dips and sharp folds, but in the Pocono Plateau 

 Region are nearly horizontal or only gently folded. The soils for the 

 most part are residual, and are essentially similar to those of the 

 Piedmont. There is much bare rock on the higher ridges and 

 steeper slopes. In the Pocono Region the soils are largely of glacial 

 origin. 



I have had no direct personal experience with the Orthopteran 

 fauna of this district and consequently am dependent for information 

 regarding its character upon the reports of other collectors. The 

 chief sources of information are the records included in the New 

 Jersey list and the collection of the Academj^ of Natural Sciences, 

 the latter including collections of Stewardson Brown and Witmer 



* The one exception to this statement, Melanoplus differentialis, represents 

 an introduction from the West. 



