Nineteenth Report 
State Entomologist of Minnesota 
TO THE GOVERNOR e/ 
/ 
/ 
By A. G. RUGGLES 
SUBJECT INDEX 
Page 
General report on the activities of the entomologist, including insect conditions 
andedstinancialstatement., by. (Gy ug eless-s)-1-.- bers. ie stele el ohelensco eyel= eS 
Preliminary report on the life history and control of the potato leaf hopper 
Empoasca mali LeB., by A. G. Ruggles and J. R. Eyer...............-- 10 
- The red turpentine beetle in Itasca Park by S. A. Graham.................. 15 
Effect of physical factors in the ecology of certain insects in logs, by S. A. 
(Gant nichgeh saxo or nd tees pe eat oa) ed ails Pree ROME =a Gia ee a ence Ror A BAe Cae oa een Wace ie 22 
WMeriiseasr as paresiticide:s yale alesis, Giltriets eer ay te house Sacer eee ee ainda cs eret pho AI 
Studies on the life history and biology of Perillus bioculatus Fabricius, includ- 
ing observations on the nature of the color pattern (Heteroptera, Penta- 
LoOnndae) ie bya attyarlt, micaiolit  stcynces cts ela otevons it cetaye ote acl eee ne steal 50 
Preliminary notes on the Mutillidee of Minnesota, by Clarence E. Mickel.... 97 
- -Synoptical key to the Aphididze of Minnesota, by O. W. Oestlund......... I14 
Agricultural Experiment Station 
University Farm, St. Paul, Minn. 
December 1, 1922 
