INSECT PEST SURVEY BULLETIN 
Vol. 19 
Supplement to Number 3 
May 15, 1939 
POPULATIONS AND HOST PREFERENCES OF JUNE BEETLES 
IN SOUTHERN WISCONSIN IN I 93 S 
By T. R. Chamberlin, C. L. Fluke, Lee Seaton, and J. A. Callenbach”^ 
INTRODUCTION 
The study of the flight and host preferences of June beetles of 
southern Wisconsin, which was initiated at the University of Wisconsin in 
1935 and continued in 193 & and - 1937 » was also continued in 193 ^, a year 
of flight for the "A Brood," or major brood of beetles. The methods of 
investigation adopted were essentially the same as those of 1935 * 193 &> 
and 1937* These studies were reported in the Insect Pest Survey Bulletin, 
June 15, 193^ (supplement to No, 4, vol. IS). The purposes of this work 
are also discussed there. 
The populations and host preferences of the various species of 
beetles were obtained by hand picking large numbers of beetles from the 
host plants on which they were feeding at night and determining the per- 
centage of the total number of beetles of each species taken from each 
kind of plant. Some samples were taken from trees on which many beetles 
were concentrated by shaking branches over canvas, but such samples are 
not included in the data herein presented. 
Many of the groves in which flight observations were made in 193^ 
were the same as those used in previous years; however, for various rea- 
sons, some of these had to be abandoned and others in the same neighbor- 
hood substituted. A few new localities were also selected. These groves 
were distributed over the southempart of the State between Racine on the 
east, Wyalusing on the west, Hancock on the north, and Lamont on the south 
(fig. l). The plant complex differed in the various localities to a 
greater or less extent. In selecting these groves the same plan was fol- 
lowed as formerly, that is, to choose only such groves as contained the 
maximum number of the kinds of shrubs and trees that were general in the 
locality. 
— 'Callenbach made the observations at Gays Mills, Boscobel, and 
Wyalusing; Chamberlin, Fluke, and Seaton the observations in all other lo- 
calities. This project is part of the general program for investigation 
of June beetles and white grubs being conducted cooperatively by the Bur- 
eau of Entomology and Plant Quarantine, of the United States Department of 
Agr i cult ur e , and the Wisconsin Agricultural Experiment Station through its 
Department of Economic Entomology. 
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