The Plant Bugs, or Miridae, of Illinois 
ELA TUR sel aN LG El 
Introduction 
HE list of Miridae of Illinois now 
stands at 330 species. It is apparent, 
however, that species known from 
neighboring states will eventually be found 
in IHinois. Furthermore, in the study of 
Illinois species, it was found that many 
records of these species were a great distance 
from any other previously known records. 
Hence, it was thought advisable to include 
in the keys other species and varieties known 
from the entire general region in which IIli- 
nois is situated. One hundred ten extra- 
limital species were, therefore, included, 
bringing the total number treated in this 
report to 440 species. It seems highly prob- 
able that from two-thirds to three-fourths 
of these extralimital species will eventually 
be found in this state, which would bring the 
list of Illinois Miridae to about 400 species. 
In the list of insects for New York 
(Leonard 1928),+ I recorded 296 species of 
Miridae, but since publication of this list 
additional records have raised the total to 
316. A list of Miridae for the District of 
Columbia and vicinity (Knight & McAtee 
1929) records 200 species of Miridae within 
a 25-mile radius of Washington, D. C. The 
state of Illinois, which includes within its 
borders the cypress swamps about Cairo and 
the northern tamarack bogs bordering Wis- 
consin, represents an ecological range scarce- 
ly exceeded by any other state east of the 
Mississippi River. This range undoubtedly 
accounts for the large list of Miridae. 
In number of species, the Miridae far 
exceed other families of Hemiptera. In the 
Palearctic region, where the total number 
of Hemiptera is best known, the “Oshanin 
Katalog” (Oshanin 1910) enumerates 1,078 
*Iowa State College, Ames, Iowa; Assistant Ento- 
mologist, Illinois Natural History Survey, during sum- 
mers of 1930, 1932, 1933, 1937. 
tMiridae, Isometopidae (Knight 1923b), pp. 110-35. 
species for the family Miridae and but 2,486 
species for all other families of Hemiptera 
combined. In North America, north of 
Mexico, approximately 1,500 species of 
Miridae are known; of other families of 
Hemiptera, about 2,500 species. 
Because of the fragile nature of the 
pubescence and appendages of the mirids, 
special attention had to be given to their col- 
lection. The collecting party, consisting of 
two or three members, equipped with nets, 
bottles, pinning and mounting accessories, 
and desk lamps, was usually in the field for 
periods of 10 days to 2 weeks. Each day, 
collecting was discontinued at about 4 P.Mm., 
and headquarters were set up for work in a 
hotel room where the day’s catch was pinned 
to prevent unmounted insects from _ being 
battered in transit. 
The collecting party used sweeping nets, 
each having a ring 15 inches in diameter and 
a bag of bolter’s silk. These were found 
ideal for mirids, since they excluded so little 
light from the bottom part of the net that 
the mirids did not swarm too rapidly to the 
top. Test-tube cyanide bottles about 6 inches 
long were used, with the cyanide in the 
bottom; the diameter of the tube was as 
large as could be stoppered by the operator’s 
thumb. In each tube were a few loose 
strands of cellucotton. The bugs were 
“picked” off the sides of the nets into the 
bottle, which could be conveniently stopperec 
by the thumb until emptied. 
With this group, care must be taken to 
have only a small number of individuals in 
each bottle at one time; otherwise consider- 
able pubescense is rubbed off. After the 
specimens are dead, they may be transferred 
to pill boxes or other temporary containers. 
If mirids are left in the cyanide bottle too 
long, some of the yellow and orange colors 
change to deeper tones, sometimes to red. 
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