8 PSYCHE [February 
paratively warm weather, under the guardianship of the mother; and, if more than 
one brood appears during a season is only the produce of the same pair that raised 
the first.” Mr. Scudder also refers to the effect of elevation, defining the subalpine 
and alpine areas of Mt. Washington. 
In 1888 Prof. Wm. M. Davis and Mr. Scudder published a map showing the 
isothermal lines and faunal areas of New England. A modification of this map in 
which the areas defined as the “Ordinary southern limit of the Canadian” and the 
“Ordinary northern limit of the Alleghenian” fauna are united to form the Transition, 
leaving the restricted Alleghenian to constitute the Upper Austral, represents practi- 
cally the present faunal zones as defined by Dr. C. H. Merriam, except that the whole 
Cape Cod region would be included in the Upper Austral, a feature which, from an 
entomological standpoint will probably prevail, and which is strengthened by a study 
of the distribution of New England locusts by Mr. A. P. Morse (Psyche, VIII, 315, 
1899). In this paper the limits of the Upper Austral are locally increased. An area 
extending northward from Narragansett Bay to the Valley of the Merrimack near 
Lowell, and north almost to Manchester, N. H., is termed the ‘‘ Dilute Carolinian 
locust fauna.’ From a Dipterological standpoint this is especially interesting as I 
am not only finding a number of Upper Austral but even Lower Austral species in 
this area. 
In taking up the subject of insect distribution in New England, a region which 
was covered with ice during the glacial period, we must first consider the supposed 
source of the present fauna. ‘The southeastern United States has been designated 
by Mr. C. C. Adams (Biol. Bull. HI, 125, 1902) and others, as the probable centre 
of geographical distribution of the flora and fauna of the eastern United States, from 
which radiated the three primary paths of dispersal — the Mississippi valley, the 
coastal plain, and the Appalachian Mountains and adjacent plateau, the coastal 
plain being finally occupied by forms now placed in the Upper and Lower Austral, 
the former extending along the New England coast at least as far as Cape Cod and 
Plymouth if not farther, and up the Connecticut valley to Springfield. The Transi- 
tion, which in the southern and middle states is confined to the more mountainous 
portions, spreads over the greater part of New England, leaving the Green Mountains, 
the White Mountains northward, and the northern half of Maine in the Boreal zone. 
In further pursuing the subject of life zones we can look upon the boreal as 
receding, losing perhaps more from the despoliation of our forests and the results 
thereof, than either the Transition or Austral. There is, on the other hand, a natural 
tendency for insects to migrate northward. This is exemplified by the spread of the 
Brown-tail Moth which has extended to Nova Scotia, while to the southward it has 
