MORSE: ORTHOPTERA OF NEW ENGLAND. 257 
Scudder, S. H. "The Distribution of Insects in New Hampshire," in Hitch- 
cock, Final Rept. Geol. N. H., vol. 1, chap. 12, p. 331-384, 2 maps, 1874. 
Hoffman, Ralph. Guide to the Birds of New England and Eastern New 
York, p. 13-17, map, 1904. 
Allen, G. M. "The Faunal Areas of New Hampshire," in the "Birds of 
New Hampshire," Proc. Manchester Inst. Arts and Sciences, vol. 4, pt. 1, 
p. 36-53, 1902. 
Morse, A. P. "The Distribution of the New England Locusts." Psyche, 
vol. 8, p. 315-323, map, 1899. 
Colonization of New England; Dispersal Routes. 
It is believed that the present land surface of New England 
underwent complete glaciation. In that case the existing distri- 
bution of its Orthoptera was brought about by dispersal from 
beyond its limits. The boreal and transition species, pushed 
southward by the advancing cold of the Glacial Period, probably 
found no great difficulty in immediately following at close quar- 
ters the diminishing ice-sheet in its retreat northward, and spread 
over the land surface as fast as it became clothed with vegetation 
and the physical conditions permitted. The later advent of the 
austral species, however, was probably along more definite 
routes. 
Whether the ice-sheet at its farthest extent reached the sea, or 
whether it was bordered by a broad land surface extending to the 
edge of the continental shelf, may never be positively known; 
but there can be no doubt that at some time in the past geological 
history of the continent, and in a comparatively late time, a wide 
sandy plain extended northeast from New Jersey to the Grand 
Banks of Newfoundland. 
Such a condition is indicated by the discontinuous distribution 
of many plants and animals peculiar to sandy districts, some of 
which are known today only from the extremes of this territory 
— New Jersey and Newfoundland — others from various inter- 
mediate but still widely separated points. With the wearing 
down and subsidence of this part of the continent, the distribu- 
tion of these species, at one time continuous, was broken up, until 
they now remain in scattered local colonies maintaining an exist- 
ence only in especially favorable spots (e.g., among Orthoptera, 
Conocephalus saltans, Hesperotettix hrevipennis, Hippiscus rugo- 
