4 IOWA STUDIES IN NATURAL HISTORY 
conforms to Van Duzee’s Cheek List and the system of nomencla- 
ture employed by him has been followed in the main. 
The principal works consulted in the preparation of this paper 
are included in the Bibliography which contains not only refer- 
ences to Iowa species but to other forms as well. 
In order to secure data and material for comparison and 
study, collecting has been done and observation made in different 
parts of the state for several summers past. In this way a great 
mass of material has been obtained. Since little more than 
lists of the Iowa species of this group have heretofore appeared, 
it is hoped that the information contained in this paper concern- 
ing the Iowa forms of this interesting group may be brought 
down to date and, perhaps, give an impetus to future work on 
Towa Hemiptera. 
In presenting this paper the writer desires to gratefully 
acknowledge his deep sense of obligation to Professor H. F. 
Wickham for continued assistance, suggestions and helpful eriti- 
cism as Well as for many specimens and valuable literature. 
Dr. G. F. Kay, Director of the Iowa Geological Survey, has 
made possible the securing of much material by granting the 
writer the privilege of collecting insects in many parts of the 
state while undertaking another line of work expressly for the 
Survey. 
Miss Jane E. Roberts, University Librarian, has aided in 
securing books and papers essential in the preparation of this 
work. 
Messrs. EK. P. Van Duzee, H. G. Barber, H. M. SD entens J. R. 
de la Torre Bueno, C. E. Olsen and W. L. McAtee all have been 
of assistance with helpful correspondence and specimens. 
To Professor B. Shimek, Head of the Department of Botany ie 
the State Universty, the writer is indebted for the determina- 
tion of most of the plants cited in these pages. 
In addition to those above mentioned, the following have fur- 
nished specimens for study and comparison: N. K. Bigelow, 
L. L. Buchanan, H. E. Ewing, J. L. Horsfall, O. W. a 
R. L. Webster and A. W. Lindsey. 
Mrs. Stoner who has accompanied the writer on numerous ecol- 
lecting trips has taken many specimens and has continually 
given encouragement and aid. 
