346 ANNUAL REPORT S^^THSONIAN INSTITUTION, 1940 



beyond the border of Tennessee and eastward through Georgia into 

 the northeast corner of South Carolina with an isolated infestation 

 in the vicinity of Thomasville in southern Georgia. 



Its distribution in 1922 was Imown to have increased 70,000 square 

 miles, principally westward and northward with a slight increase in 

 the infested area to the southwest. The annual distribution outlined 

 herein for the subsequent years is based upon records of its discovery 

 in new areas as reported by entomologists and growers and others, and 

 is not the result of a planned survey as was the case during 1921 and 

 1922. Reports received in 1923 showed an extension of invaded terri- 

 tory of approximately 26,500 square miles, mainly northward with no 

 additional territoiy to the south or west reported as infested. 



In 1924 the beetle had extended its range, 85,500 square miles of 

 newly infested territory being reported from all directions. This was 

 the most extensive distribution reported for any 1 year during the 20 

 years it has been known to occur in the East. Again, as was the case 

 in former years, the greatest spread was to the north, reaching into 

 Ohio almost to Lake Erie and eastward into the southwest comer of 

 Pennsylvania. 



During the next 2 years the records of new infestations were unusual 

 in two respects: The additional square miles reported infested were 

 comparatively small, considering the large territory now infested from 

 which the insect could spread, and the spread extended to the east and 

 west only, no new territory being invaded in the south or north. In 

 1925 additional reports came only from east of the infested area. 



The factors which influenced the reported slower advance of the 

 beetle into new territory during 1925 and 1926 were absent the follow- 

 ing year. In 1927 the beetle was found to have reached the shores of 

 Lake Erie in southwestern New York and was reported from Canada. 

 It now threatened the great bean-growing area of Michigan and was 

 present on the Atlantic coast in southeastern Virginia. Westward, 

 however, the spread was confined to a narrow strip in Tennessee, Ken- 

 tucky, and Indiana. The total extension of its range during the year 

 was 80,000 square miles and this spread was the second greatest in its 

 history. The spread in 1926 was confined to about 56,000 square miles 

 and was notable because the market and canning bean-growing sections 

 of eastern Pennsylvania, New Jersey, Maryland, and Delaware were 

 invaded. 



After 1928 the insect's spread during each of the following 4 years, 

 judging from the reports, amounted to an average annual increase in 

 its range of about 20,000 square miles. By 1930 and 1931 it had reached 

 the Mississippi River in Kentucky and had moved farther in a north- 

 easterly direction into New York and Connecticut. In 1932 it was 

 found on the eastern border of Illinois and to the west of northern 



