4 ILLINOIS NATURAL History SURVEY BULLETIN 
tound to produce two or more generations 
in one season. 
Lygus oblineatus (Say) may produce two 
or three generations in one season; Halticus 
bracteatus (Say) breeds continuously during 
the warm season and is credited with five 
generations in South Carolina. Adelphocoris 
lineolatus (Goeze) rears two generations in 
a season on alfalfa and sweet clover. Neobo- 
rus amoenus (Reuter) rears two genera- 
tions in one summer on white ash. The 
cotton flea hopper, /Psallus  seriatus 
(Reuter), breeds continuously as long as the 
succulent host plants remain green. 
Hibernation 
A majority of mirid species pass the 
winter in the egg stage. Usually the eggs 
are embedded in some part of the host plant. 
In the hop mirid, Paracalocoris hawleyt 
Knight, the female bugs embed their eggs in 
the poles used for support of the host vines. 
The writer observed several females ot 
Neo!lygus johnsoni Knight laying eggs in the 
soft, punky stubs formed by the breaking off 
of old dead limbs on the host tree, hornbeam 
(Carpinus caroliniana). Many species, such 
as Lopidea davisi Knight, Labopidea alli 
Knight and Adelphocoris lineolatus, lay eggs 
in stems or leaves of herbaceous plants and 
pass the winter in the dry stems. The apple 
redbug, Lygidea mendax, Heterocordylus 
malinus and Neolygus communis place eggs 
in the living cambium on branches of the 
host tree where they pass the winter. 
Mirid eggs, fig. 2, have a relatively im- 
pervious chorion which permits them to 
remain viable for several months, although 
embedded in material which is almost com- 
pletely desiccated. 
Relatively few species hibernate as adults. 
Stenodema vicinum (Provancher) and S. 
trispinosum Reuter are known to do so and 
no doubt other members of the genus do 
likewise. Adults of Lygus oblineatus, L. 
vanduzeei Knight, L. plagiatus Uhler, L. 
pabulinus (Linnaeus), L. campestris (Lin- 
naeus) and L. rubicundus (Fallen) have all 
been taken in hibernation, and it seems a 
characteristic of the genus to overwinter in 
the adult stage. Species of the subgenus 
Camptobrochis of Deraeocoris hibernate as 
adults, so far as known, with D. nebulosus 
(Uhler), D. poecilus McAtee, D. histrio 
(Reuter), D. nubilus Knight frequently 
taken in winter. Here again hibernation ap- 
Voli 22, Arta 
pears to be a group characteristic. Dicyphus 
vestitus Uhler and D. discrepans Knight 
also have been taken in hibernation. 
Feeding Habits 
Probably a majority of the species of 
Miridae are plant feeders, but a large num- 
ber are now known to be chiefly predacious. 
The predacious habit is only partially devel- 
oped in certain species and thus insect blood 
serves merely to. supplement the sap ob- 
tained from particular food plants. In the 
genus Deraeocoris the different species ap- 
pear to be chiefly predacious; D. aphidi- 
phagus Knight feeds on the elm aphid, 
Eriosoma americanum Riley, and its honey- 
dew; D. nitenatus Knight feeds on the 
woolly apple aphid, Eriosoma lanigerum 
(Hausmann); D. pinicola Knight feeds on 
Chermes pinicorticis (Fitch). It seems high- 
ly probable that most members of the sub- 
family Cylapinae are predacious or myce- 
tophagous; namely, species of Fulvius and 
Peritropis and Cylapus tenuicornis Say; 
known species of these genera are normally 
found about dead trees, hiding in crevices 
of the bark on logs and stumps. In the large 
genus Phytocoris, several species are known 
to be predacious, particularly the dark- 
colored, bark-inhabiting ones. Fulton (1918, 
pp. 93-6) demonstrated that Pilophorus per- 
plexus Douglas & Scott feeds freely on apple 
aphids, three nymphs having reduced a 
colony of 50 aphids to 6 within 2 days. 
Among the plant feeders, probably the 
greater number of species are limited to a 
single host, or to a genus of plants, while 
a very few, such as Lygus oblineatus and 
Halticus bracteatus have a wide range of 
food plants. Even among species which 
always breed on a single host plant, a general 
dispersal of individuals usually takes place. 
Following the time of emergence and mat- 
ing, individuals of T'ropidosteptes cardinalis 
Uhler, Lopidea staphyleae Knight and others 
have been observed to migrate from their 
host plant to shrubbery in the general vicin- 
ity; thence they doubtless become dispersed 
over wider territory and to new plants, 
although, in the normal course of their life, 
they eventually return to suitable growth 
of the preferred host plant for the purpose 
of oviposition. 
Since a majority of species of Miridae are 
definitely limited to a single species of plants 
or at least a genus of plants, we may expect 
