460 PROCEEDINGS OF THE ACADEMY OF [June, 



Cenchrus trihuloides, species of Cyperus and Carex, sand-myrtle, 

 Hudsonia tomentosa, and prickly-pear cactus, Opuntia opuntia. Fur- 

 ther back these are replaced by the bayberry, Myrica carolinensis, 

 thicket formation. This extends close to the edge of the salt marsh, 

 but is separated from the latter by a usually narrow zone consisting 

 chiefly of Iva oraria and Baccharis haliriii folia, the distinctive salt- 

 marsh border plants. The dune depressions harbor a hydrophytic 

 flora similar to that characteristic of the Submaritime zone. 



The chief distinguishing features of the Orthopteran fauna of the 

 beaches are positively the abundance of T rimer otropis maritima, the 

 presence of a peculiar race or possibly species of Schistocerca and the 

 relative frequency of Schistocerca americana; negatively the absence 

 or scarcity of several mainland species. 



The following list gives all the species which to my knowledge 

 have been taken or recorded from the beaches, excepting, however, 

 all forms that I regard as more properly belonging to the Submari- 

 time faunule. 



Orphidella speciosa Schistocerca sp. cf. obscura 



" pelidna Melanoplus femur-rubrum 

 Chortophaga viridifasciata " femoratus 



Hippiscus phoenicopterus Scudderia texensis 

 Dissosteira Carolina " furcata 



Trimerotropis maritima Conocephalus robustus 

 Psinidia fenestralis " triops 



Scirtetica marmorata Orchelimum vulgare 



Schistocerca americana Xiphidium striatum 



There is a close correspondence between the distribution of Orthop- 

 tera on the beaches and that of the vegetation already referred to. 

 On the outermost dunes in the Ammophila arenaria areas Trimero- 

 tropis maritima abounds to the almost total exclusion of other species. 

 Further back, where the Ammophila begins to be replaced by a mixed 

 vegetation, the Trimerotropis gradually becomes reduced in numbers, 

 its place being taken by such species as Psinidia fenestralis and 

 Dissosteira Carolina, both of which are abundant on bare sandy spots. 

 The vegetation in this zone is a very open one and consequently 

 there are numerous exposed areas of dry sand on which these forms 

 delight to rest. Still further back from the sea we come to the 

 bayberry thickets in which the peculiar maritime species or variety 

 of Schistocera is of frequent occurrence. This form of the genus is 

 apparently restricted to the beaches. In coloration it closely resem- 

 bles S. ruhiginosa of inland districts, but is always much larger, and, 

 as Mr. Rehn has suggested to me, may represent a non-striped race 



