ECOLOGY OP ISLE ROYALE. 299 



REPORT ON THE ISLE ROYALE ORTHOPTERA OF THE 1905 



EXPEDITION.- 



ALBERT P. MORSE, RESEARCH ASSISTANT^ CARNEGIE INSTITUTION OF 



WASHINGTON. 



1. General Remarks: 



The orthoptera secured by the University Museum expedition of 1905 

 to Isle Royale consist of representatives of 13 species. Of these, one 

 is a cosmopolitan roach, tlie Croton-bug, BlaUella germanica, doubt- 

 less introduced in merchandise through man's agency. The others, with 

 a single exception, are boreal Acridians characteristic of the cooler 

 parts of central and eastern North America, whose presence in this 

 locality was either known or to be confidently expected. The exception, 

 Melanoplus alaslcanus, is a species hitherto known only from the North- 

 west, whose presence on Isle Royale, in sufficient numbers to make it 

 appear to be the dominant species of its genus there, was, to say the 

 least, unlocked for. It would be of much interest in this connection to 

 know the status of this species on the adjoining northern mainland. 



Some striking variations are present in the representatives of certain 

 species and will be found noted in the following list. In general, there 

 seems to be a tendency toward an increased duskiness of coloring as 

 shown by Camnula pellucida, Hippiscus titberoulatus, and Circotettix 

 verruculatus (all geophilous species), due perhaps to humidity, per- 

 haps to environmental coloration ; also, as compared with eastern ma- 

 terial, the specimens are of relatively large size, particularly in the 

 cases of Melanoplus extremus and fasciatus. 



The locust societies represented consist of campestral and thamnoph- 

 ilous groups, though all of the species are to be obtained in the clear- 

 ings or about their edges, rather than in the forest. 



The thamnophile species are Ghloealtis conspersa and aidominalis, 

 Melanoplus fasciatus and Tvuroni. The campestral species, notwith- 

 standing the generally forested character of the country, are more 

 numerous and consist both of phytophilous and geophilous species. In 

 the damper situations occur Stenohothrus curtipennis, Mecostethus line- 

 atus, Melanoplus extremus and femoratus. In drier places Oamrmla 

 pellucida, Melanoplus alaskanus, and Hippiscus tuberculatum are to be 

 found. Characteristic of the bare rock ridges is the saxicolous Circo- 

 tettix verruculatus. The two latter species, with their strikingly colored 

 wings and noisy flight, are the most conspicuous members of the orthop- 

 terous fauna of the island. 



The 1904 expedition secured examples of a Tettigid (Tettix acadicus) 

 and of a wingless JjOcuBtavian^-GeuthophihiS secUvsus. The species of 

 Geuthophilus usually inhabit damp, dark places, under bark, in hollow 

 logs, etc., and are among the most characteristically sylvan of our or- 

 thoptera. 



