-631- 
JAPANESE BEETLE 
The 1938-39 brood of the Japanese beetle ( Popillica japonica "Serna . ) was 
characterized hy a consistent retarded development in each of the stages. Fol- 
lowing an unusually late development of larvae in the fall of 1938* a higher— 
than-normal percentage of larvae entered hibernation as second instars. A 
somewhat wet, cool spring appears to have further retarded development so that 
general emergence of beetles in 1939 was from 10 days to 2 weeks la tor than 
normal* . . 
At the close of the 1939 beetle season the area of general distribution 
was estimated to occupy approximately 16,300 square miles, an increase of 1,183 
square miles over that of the previous year. This area "’as distributed among 
the various States as follows! Connecticut, 286 square- miles; New York l,l4l; 
New Jersey, 7 » 2^0 ; Pennsylvania, 5*013l Maryland, 1,546; and Delaware, 1,064. 
The following points roughly define the limits of the area of general distribu- 
tion; Lincoln and Edwards ville, Del; Church Hill, Elkridge, Sllicott City, 
Lutherville, and Norris ville, Md. ; Brogueville, West York, New Kingstown, New 
Buffalo, Hershoy, Hamburg, Nazareth, and Stroudsburg, Pa,; Andover and Pompton 
Lakes, N. J.; Suffern and West Point, N. Y. ; and Danbury and Stratford, Conn. 
The regional concentration of beetles varied markedly throughout the area 
of general distribution, as indicated in the accompanying map. As has been the 
case for the last several years, the infestation was nost-severe in northern 
Delaware, northeastern Maryland, and extreme southeastern Pennsylvania. Within 
this area the infestation, generally speaking, was , of about the same severity 
as that observed in 1938, with heavy foliage injury advancing from 1 to 5 miles 
beyond points observed the preceding year. Throughout the remainder of the 
area -of general distribution the infestation was somewhat spotty, as compared 
with 1938, in many areas appearing to be heavier than in 1938, while in others 
it was lighter. On Staten Island and in most of the Now York metropolitan area 
the infestation was not as heavy as the previous year, while north of the city 
and throughout Connecticut there appeared to bo a decided increase* For the 
first time in sev ral years an increase was observed in the oldest infested 
area in the vicinity of Moores town, N. J, 
A survey of a number of secondary centers of dispersal situated on the 
Eastern Shore of Maryland and Virginia revealed that a considerable amount of 
dispersal had taken place. The largest area generally infested involved approxi- 
mately 4-15 square miles in Somerset and Worcester Counties,- Md. , and Accomac 
County, Va. 
In New England there was in 1939 a general increase in beetle abundance at 
practically all of the known colony sites, the increase being especially notice- 
able throughout the southern half of that area. General population increase 
and local dispersion appears to have occurred at such large centers as metro- 
politan Boston, Mass., Providence, R. I,, and New Haven and Bridgeport, Conn. 
The natural dispersion of the insect in southwestern Connecticut is gradually 
meeting and fusing with localized colonies in suburban areas along Long Island 
Sound. (C. H. Hadley, Bureau of Entomology and Plant Quarantine, U. S. D. A.) 
Trapping activities outside of the. main Japanese beetle infested area dis- 
closed a very moderate spread of infestation during the last year. The 1939 
