216 
Psyche 
[December 
On the other hand, the westward spread of the two-gen- 
eration strain of the borer from the eastern end of the Is- 
land has been more than twice as rapid. In 1927, Matti- 
tuck, on the north fork, and Southampton, on the south 
fork, formed the western limits of the two-generation infes- 
tation, while in the late summer of 1933 evidences of this 
strain were encountered as far west as Greenvale in Nassau 
County, a distance of about 60 miles. Consequently, there 
Fig. 1. Map showing distribution of both broods of the European 
Corn Borer on Long Island 
exists (1933) an overlapping of the two strains in an area of 
approximately 275 square miles a little west of the center 
of Long Island. In the townships of Oyster Bay in Nassau 
County and Babylon, Islip, Huntington, and Smithtown in 
Suffolk County evidences of both the one-generation and the 
two-generation strains have been found. 
Since 1928 annual “infestation surveys” have been made 
to determine the intensity of European corn borer infesta- 
tions in corn in both the single-brood and the double-brood 
districts of Long Island. In the former the surveys were 
conducted in midsummer, while in the latter they were made 
