ECOLOGY OF NORTHERN MICHIGAN. 69 



As is evident from Mr. Ruthven's field notes on the general character 

 of the stations, and also from a consideration of the station lists of Orthoptera, 

 almost every station contains two or more locust societies. These societies 

 comprise one or more characteristic species of locusts which find their pre- 

 ferred haunts within a relatively narrow range of physical conditions and 

 are practically characteristic of such habitats. It should be pointed out, 

 however, that in the heart of its range a species is usually more generally 

 distributed, and less restricted to its special habitat, than elsewhere; further- 

 more, that accidental occurrences are not infrequent and can" be correctly 

 estimated as such only by careful observation or experience. "One swallow 

 does not make a summer," and the capture of a single specimen of a locust 

 in a given locality does not necessarily indicate either an austral or a boreal 

 climate, a campestral or a sylvan habitat. 



It is scarcely necessary to state that the abundance and extent of the 

 area occupied bj^ the various elements of the locust fauna will inevitably 

 be affected by the physical and organic agencies controlling the condition 

 of the environments they inhabit, and, other things being equal, will change 

 as they change. On the advent of new conditions one of three things 

 will happen: either the species will become adapted to its changed environ- 

 ment, will emigrate, or will die out in that particular spot — probably the latter. 

 There is every reason to think that with increasing deforestation of the terri- 

 tory, the thamnophilous locusts will increase in numbers; and that, if settle- 

 ments and clearings multiply, so will the campestral locusts. 



The avenue of ingress of the orthopterous fanua into this territory, it 

 is believed, was on the southwest, along the continuous land surface, follow- 

 ing the retreat of glacial conditions. This avenue was probably the only 

 practicable one open to the flightless thicket-dw^elling forms, and was doubtless 

 followed by most, or all, of the flying species as well. 



For further information in regard to the biology of the Orthoptera herein 

 mentioned, the following works should be consulted, in addition to those 

 already referred to: 



Blatchley, W. S. — The Orthoptera of Indiana. — 27th Annual Report of 

 the Department of Geology and Natural Resources of Indiana. 



Morse, Albert P. — Notes on the Acridiidae of New England. — Psyche, 

 vols. VII, and VIII. 



The former of these contains a valuable bibliography. 



2. STATION LIST. 



Station I. Beach of Lake Superior. Species taken: Chloealtis abdomi- 

 nalis, Camnida pellucida, Circotettix verruculatus , Melanoplus atlanis and 

 Melanoplus femoratus. 



Habitats represented and characteristic species. 



1. Exposed rock or soil surfaces: Circotettix verruculatus, (Camnula 



pellucida) . 



2. Grassy places — dry: Melanoplus atlanis and Camnida pellucida. 



3. Grass}^ places — moist: Melanoplus femoratus. 



4. Thickets — forest edge: Chloealtis ahdominalis. 



Station II. North Slope of First Range. Species taken : 

 Slib. 2. — Hardwood Forest. — Tettix brunneri. 

 Habitats represented and characteristic species. 



The single species taken is not typical of forested enviromnent, usually 

 occurring: on bare soil. 



