12 Ittinois NATURAL History SuRvVEY BULLETIN 
species, such as Muiris dolabratus (Lin- 
naeus) are widely distributed and feed only 
on grasses. The range of such species ex- 
tends over most of the state. 
Other plant bugs of this subfamily feed 
on sedges and rushes, as for example, Muimo- 
ceps insignis Uhler and Teratocoris discolor 
Uhler, and these are restricted to such local 
areas as have marsh conditions. 
In the bog region of northeastern IIlinois, 
we have many marshes which are excellent 
collecting grounds for these mirids. While 
these mirids are not restricted to this region, 
they are found there more frequently and in 
greater abundance than in other localities 
of the state. The sand area along the shore 
of Lake Michigan combines a great variety 
of grass, sedge and rush species, and offers 
excellent collecting for some of the rarer 
Mirinae. 
Widely Distributed Species 
A number of favorite plant bug hosts 
grow in almost every locality in Illinois, and 
include such familiar forms as ragweeds, 
cocklebur, willows and some of the grasses. 
In this category are a large number of 
weeds, herbs and shrubs. Many of the Mir- 
Vol. 22 Artes 
idae feeding on these hosts have an equally 
wide distribution: Lygus oblineatus (Say), 
feeding on a great variety of herbs and 
shrubs; Reuteroscopus sulphureus (Reuter), 
feeding on the cut-leaf ragweeds (4d mbrosia 
spp.); Ilnacora stalii Reuter, feeding on 
cocklebur; and many others. The distribu- 
tion map of L. oblineatus, fig. 11, ‘shows the 
wide distribution of this species and serves 
as a check map for comparing the distribu- 
tion of other Miridae. 
Collecting Notes 
It will be seen from the above that the 
Miridae inhabit practically all the plant 
communities in Illinois, showing a preference 
for areas that are borderline between prairie 
and forest, and that are in the developmental 
stages approaching the climax forest. 
Profitable collecting for a large variety 
of plant bug species may therefore be found 
in the forest edge around clearings, fig. 12, 
or in country with fields, fencerows and 
woods intermingled, fig. 13. A second equal- 
ly profitable type of area is that along small 
streams where a floodplain forest is grow- 
ing. In both types of situation, many host 
species are concentrated in a small area. 
Economic Status and Control* 
The past 25 years have witnessed a decid- 
ed increase in the number of Miridae that 
are recognized as economic pests. These are 
sucking insects which pierce plant tissues and 
feed on cell liquids, fig. 14. 
One of the Miridae of greatest economic 
importance in IIlinois is the tarnished plant 
bug, Lygus oblineatus (Say). This insect 
Causes serious damage to the peach crop. 
The adult insects hibernate in the fall and 
leave their winter quarters early in the 
spring. They feed on the newly set peaches 
just at the time when the peach petals have 
fallen, and they are responsible for the 
blemish commonly known as catfacing, fig. 
15. The area surrounding each feeding 
puncture in the side of the peach grows very 
little, and on it ordinary peach fuzz does not 
develop. The result is that when the peach 
is ripe there is a bare, sunken area, some- 
times as much as a half inch across, in the 
_*W. P. Flint, Chief Entomologist, Illinois Natural 
History Survey and Agricultural Experiment Station, 
cooperated in writing this section, supplementing it with 
his knowledge of economic insect control methods in IIli- 
nois over a long period of years. 
side of the peach. Although these blemishes 
do not affect the quality of the peach very 
much, they throw the fruit out of grade. In 
certain years as much as 7 to 8 per cent of 
all peach fruit in an orchard is affected. 
Dusting with very fine sulfur at the time 
petals are falling has shown some benefits 
in peach orchards. 
This insect also feeds on the new shoots 
of nursery stock, causing what is called 
“stopback” or “dieback.” It injures a num- 
ber of fruits by feeding on the buds. The 
feeding punctures of this species may cause 
malformation in the flowering buds of asters 
and strawberries. In orchards the insect may 
attack the buds and young fruits of apples 
and peaches. It also feeds on beet, chard, 
celery, bean, potato, cabbage, cauliflower, 
turnip, salsify, cucumber, cotton, tobacco, 
alfalfa, many flowering plants, and most 
deciduous and small fruits—more than 50 
economic plants, besides many weeds and 
grasses. 
The tarnished plant bug is such a general 
feeder and so widely distributed, and is at 
