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HYMENOPTERA 619
usually present, rarely vestigial or absent. Antennre of males 12-segmented; of
queens and workers ll-segmented. MOLtth parts normal; clypeus mayor may
not extend between frontal carinre; mandibles simple or toothed; small or wide.
Tibire of middle and hind legs absent or simple. Wings usuallY present or rarely
absent in reproductives; fore pair with one closed cubital cell. Abdomen with
distinctly two-segmented pedicel; gaster short; cerci present in males of most
genera; male genitalia partly concealed or exserted; sting present. Stridulatory
organ present in many genera. Pupre naked.
These ants are mosUy phytophagous and feed upon seeds which they gather
and store. Many are fungus growers. These latter, belonging t.o the neotropical
tribe ATTII, cut leaves which they carry to their nests and upon which
fungi are cultivated for food. Some eat the tender bark of trees, and others are
general feeders thai tend aphids, coccids, and lycrenid caterpillars for honeydew,
while a few are carnivorous. Many are household pests. Practically all of the
following important genera are cosmopolitan: Anergates Forel (Palrearctic),
Atta Fab. (Neotropical), Cremastogaster Lund, Leptothorax Mayr, Massor Forel,
Myrmecina Curtis, Myrmica Latr., Monomorium Mayr, Pheidole Westwood,
'Pogonomyrmex Mayr, Solenopsis Westwood, and Tetramorium Mayr.
The social parasitic ant, Anergates atratulus Schrank, 2.5-3.0 mm., shares
the nests of the turf ant, Tetramorizem c&3spitum (Linn.), 2.5-8 mm., which
nests in sandy fields or under stones and makes small mounds. The former
rarely has queens, and the males are apterous. Both occur in Europe, and the
latter has been introduced into America. Members of the genus Atta are variously
called "leaf cutters" because
they cut leaves and drop
them to the ground, "parasol
ants" from the fashion of holdlng
the leaves in the air over
the bodies while carrying the
leaves to the subterranean nests,
and "fungus growers" from the
culture of fungi on the chewed­
up leaves which are mixed with
Pogonomyrmex
FIG. 237. Wing of the California harvester ant,
Pogonomyrmex californicus (Buckley).
excrement and converted into suitable compost for the growing of hyphre and
the production of swellings or bromata which are eaten by the ants. The
hyphre are carried to new nests by the queens and are characteristic of the
species.
Members of the genus Cremastogaster have various habits, the temperate
species frequently nesting in the ground under stones while certain tropical
species build globular paper-like nests. C. scutellaris Olivier, 3.5-10.0 mm. long,
is the commonest European species. The acrobat ant, C. lineolata (Say), and
its numerous subspecies and varieties occur throughout North America. Leptothorax
emersoni Wheeler nests close to and connects with the burrows of its
host, Myrmlca ruora (Linn.) subsp. orevinodis Emery, the bodies of which it
grooms and from which it also steals food as the host workers regurgitate in