6 PSYCHE [February 
plants to extend their range of distribution. A noticeable illustration is the spread 
of the Catalpa sphinx (Daremma catalpae). ‘The catalpa, which is a native of the 
southern States, has now become a common shade tree throughout the northern 
states. The sphinx, which has now reached New York, first made its appearance 
in the vicinity of Philadelphia in 1898, doing considerable damage. ‘The following 
year it was more abundant and an interesting feature in this connection is that at 
that time it apparently had no natural enemy, but in 1900 parasites appeared which 
destroyed fully eighty per cent of the larvee. It was therefore evident that the moth, 
in its migration northward, advanced more rapidly than its parasites, or was for the 
time immune. It would also be well to consider the effect of the attacks of native 
insects on foreign plants. 
Geographical distribution from an ecological standpoint, presents a most 
fascinating subject, made doubly interesting by its great diversity and many intri- 
cacies. Especially is this true of insects and particularly so in New England, where 
the varied surroundings within a comparatively small area, present many of the 
conditions which undoubtedly governed and limited the early dispersal of species. 
The birds and mammals have been mostly used in defining faunal areas, and while 
the areas thus defined represent what might be called the greater life zones, they are 
often too general in character to account for many of the unexpected appearances 
and peculiar variations of certain insects. A thorough ecological study of a given 
area will, no doubt, account for many if not all of these unusual occurrences, or add 
materially to our knowledge governing the conditions affecting the distribution of 
insects. 
A brief history of geographical distribution bearing on New England, shows the 
characteristic progress which has attended all lines of scientific research. It was 
Prof. Louis Agassiz who in 1854 (in Nott & Gliddon, Types of Mankind), first 
attempted to divide North America into several zoological areas. On the Atlantic 
coast he recognized four—the Arctic, including Greenland and Labrador; the 
Canadian extending from Labrador south to a line drawn across the centre of New 
Hampshire and Vermont; the Alleghenian embracing all the region from southern 
Maine to North Carolina, and the Louisianian from southern Virginia to southern 
Florida. In 1859 Dr. John L. LeConte (Smith. Contr. Knowl., XI) divided the 
United States into a number of provinces, the first attempt made from an entomo- 
logical standpoint, and based on the distribution of Coleoptera. In making these 
divisions he says: he whole region of the United States is divided by meridional or 
nearly meridional lines into three or perhaps four great zoological districts, distin- 
guished each by numerous peculiar genera and species which, with but few excep- 
