STATE OF ILELNOLS 
Dwicut H. GREEN, Governor 
DEPARTMENT OF REGISTRATION AND EDUCATION 
FRANK G. THompsON, Director 
BOARD OF NATURAL RESOURCES AND CONSERVATION 
FRANK G. THOMPSON, Chairman 
WILLIAM TRELEASE, D.Sc., LL.D., Biology 
Ezra J. Kraus, Ph.D., D.Sc., Forestry 
L. R. Howson, B.S.C.E., C.E., Engineering 
ARTHUR CuTTs WILLARD, D.Eng., LL.D., 
President of the University of Illinois 
Epson S. Bastin, Ph.D., Geology 
Rocer ApAMs, Ph.D., D.Sc., Chemistry 
NATURAL HISTORY SURVEY DIVISION 
Urbana, Illinois 
SCIENTIFIC AND TECHNICAL STAFF 
Tueovore H. Frison, Ph.D., Chief 
Section of Economic Entomology 
W. P. FLintT, B.S., Chief Entomologist 
C. C. Compton, Ph.D., Associate Entomol- 
ogist 
M. D. Farrar, Ph.D., Research Entomolo- 
gist 
J. H. Biccrr, M.S., Associate Entomologist 
S. C. CHANDLER, B.S., Southern Field Ento- 
mologist 
James W. AppLe, M.S., Northern Field 
Entomologist 
B. G. Bercer, M.A., Assistant Entomologist 
H. B. Petty, Jr., B.A., Assistant, Entomol- 
ogy Extension 
C. J. WEINMAN, Ph.D., Research Fellow in 
Entomology 
WILLIAM H. Hasse, Entomological Assistant 
Joun M. Wricut, B.A., Junior Entomolo- 
gist (U. S. B. E. P. Q. and Commodity 
Credit Corporation, cooperating) 
Section of Insect Survey 
H. H. Ross, Ph.D., Systematic Entomologist 
Cart O. Mone, Ph.D., Associate Entomolo- 
gist, Artist (on leave) 
B. D. Burks, Ph.D., Assistant Entomologist 
(on leave) 
Mitton W. SANDERSON, Ph.D., Assistant 
Entomologist 
KATHRYN M. SoMMERMAN, MS., Artist, 
Entomological Assistant 
Section of Forestry 
JaMEs E. Davis, M.F., Extension Forester 
Lee E. YEAGER, Ph.D., Forester 
Section of Aquatic Biology 
Davi H. THompson, Ph.D., Zoologist 
Grorce W. BENNETT, Ph.D., Limnologist 
D. F. Hansen, Ph.D., Assistant Zoologist 
Section of Game Research and Management 
R. E. YEATTER, Ph.D., Game Specialist 
Section of Wildlife Experimental Areas 
Artruur S. Hawkins, M.S., Game Tech- 
nician (on leave) 
F. C. BELLROSE, Jr., B.S., Assistant Game 
Technician 
J. B. Low, Ph.D., Assistant Game Tech- 
nician 
W. H. Exper, Ph.D., Assistant Game Tech- 
nician 
Cooperative Wildlife Restoration Program 
(State Department of Conservation and U. 
S. Fish and Wildlife Service) 
Orro W. Tremetgr, M.A., Junior Biologist 
Section of Applied Botany and Plant 
Pathology 
L. R. TEHON, Ph.D., Botanist 
D. B. CrEAGER, Ph.D., Research Pathologist 
J. C. Carter, Ph.D., Assistant Botanist 
G. H. Boewer, M.S., Field Botanist 
Section of Publications 
James S. Ayars, B.S., Technical Editor 
ConsuLTANT: Herpetology, Howarp K. Gioyp, Ph.D., Director of the Museum, Chicago 
Academy of Sciences 
This paper is a contribution from the Section of Aquatic Biology. 
(34354—3M—11-42) 
