280 
Psyche 
[December 
hilalis Hiibn.) in the New England area have been conducted for 
several years to determine the importance of winter mortality 
as a limiting factor in the spread and injurious occurrence of this 
insect. It has been found that the spread of the insect has been 
greatest along the coast of New England and least inland from 
Fig. 1. Map showing the southern extent of the area of high winter mortality of the European 
corn borer in New England during the winters of 1922-1923 (AA) 1923-1925 (BB). 
the sea. This condition may be due in part to an ability of the 
overwintering larvae to survive more successfully along the 
coastal region where the winter temperatures due to the 
moderating effect of the ocean are less severe than farther 
inland where such a moderating effect is less noticeable. On the 
other hand no such condition may exist, and the more rapid 
spread along the coast may be the result of other causes. 
