FOREWORD 
HE Miuiridae, or plant bugs, containing 
well over a third of the species of the 
order Hemiptera, have long attracted atten- 
tion because of their abundance, their diver- 
sity of shape and the great variety of plant 
hosts they attack. Except for a few preda- 
cious species, they suck the juices from plant 
leaves and, with the leafhoppers, aphids and 
~ scale insects, rank as one of the most impor- 
, tant groups of plant sucking insects in IIli- 
nois. 
Early in 1930, a project to investigate the 
* Miridae of Illinois and to prepare a com- 
~ prehensive report on the state fauna was 
organized. Dr. Harry H. Knight, Iowa 
State College, Ames, Iowa, was enlisted as 
leader of the project to direct the initial 
intensive collecting for the group, identify 
the material and write the final report, and 
he was employed by the Survey as Assistant 
Entomologist during the summers of 1930, 
1932, 1933 and 1937 to acomplish these 
objectives. 
Intensive collecting was begun in 1930. 
Prior to this date much material had been 
assembled by earlier Illinois collectors, par- 
ticularly C. A. Hart and C. W. Stromberg, 
whose specimens in the Natural History 
Survey collection formed not only a good 
general collection of the group but also in- 
cluded several species not taken in our recent 
search. Much interesting material collected 
in Illinois by W. J. Gerhard was lent us 
by the Field Museum of Natural History, 
Chicago. 
Field work for this group followed very 
closely the pattern developed during an 
earlier study of Illinois aphids (Hottes & 
Frison 1931). Collecting was done in every 
part of the state, from south to north, east 
to west, and repeated at different seasons in 
an attempt to capture species which might 
be restricted to certain periods of the year 
or to limited local habitats. Using known 
mirid host plants as a guide, we attempted 
to collect from every species of probable 
host in every locality visited. 
This procedure was followed in 1930 and 
1932. In 1931, drought conditions reduced 
the mirid population to a low ebb, making 
collecting for this group impractical. In 
1934, 1935 and 1936, intensive collecting 
for leafhoppers turned up many more Miri- 
dae, including a large number of new records 
for Illinois. A total of about 20,000 speci- 
mens was accumulated, including the 5,000 
specimens already in the collection before 
our drive for this group began. All mem- 
bers of the Insect Survey Section staff have 
at various times aided with the field work 
and preparation of material for identification 
and preservation. 
Much of the work of final identification 
of material and completion of the manuscript 
was done by Dr. Knight at Ames, Iowa, 
while not attached to the Survey, and I wish 
to express our gratitude to him for spending 
so much of his own time in bringing this 
project to a successful conclusion. 
Several members of our staff in the Insect 
Survey Section also have contributed greatly 
to the final manuscript. The many full illus- 
trations of Miridae are with few exceptions 
the work of Dr. C. O. Mohr, Associate 
Entomologist and Artist. Dr. Mohr and 
Miss Kathryn M. Sommerman, Entomologi- 
cal Assistant, also added many illustrations 
used to illustrate key characters and male 
genitalia. Summarizing the Illinois collec- 
tion data and adding it to the manuscript, 
modification of the keys to emphasize as 
much as possible characters which could be 
illustrated, and adapting the manuscript to 
current Survey practices represent the pains- 
taking and effectual work of Dr. H. H. 
Ross, Systematic Entomologist, and Dr. B. 
D. Burks, Assistant Entomologist. The sec- 
tion on economic status and control is in part 
the @work wots rote Wolf lint. Chiet 
Entomologist. Finally the manuscript was 
read and styling determined by the Editor, 
Mr. James 8. Ayars. 
T. H. Frison, Chief 
Illinois Natural History Survey 
