LIBRARY

758
COLLEGE ENTOMOLOGY
The respiration is cutaneous and the Iarvre live in the depths where no free
oxygen remains.
The pupre are somewhat mosquito-like with large cephalothoracic area,
bladder-like respiratory tubes, and two wide fiat anal paddles.
The phantom larvre are nocturnal and feed upon plankton consisting of both
animal and plant life and upon larger forms of animal life. During the day they
remain on the bottom. In general they are considered beneficial because of
being predacious on mosquito wrigglers and lnrvre of oiher noxious aquatic
gnats. The adults do not bite but they often appear in very great numbers
about lakes in warmer areas and become a serious nuisance, particularly at resorts.
Being attracted to lights, they swarm into the parks, villages, and buildings
and onto the occupants.
The family is a small one consisting of less than 100 named species. It is
apparently widely distributed, and many additional species probably are still
awaiting discovery. The most important genus is Chaoborus Lichtenstein
(Corethra Meigen). In Lake County, Calif., the Clear Lake gnat, C. astictopus
D. & S. (= laeustris Freeborn), is exceedingly abundant and annoying to res·
idents and vacationists during the spring and summer months.
The Kungu fly, Chaol)orus sp., appears in dense c1oud·like swarms that
move across Lake N yasa like low rain clouds. A few or as many as six of these
huge masses of flies may be seen at one time.
The mosqUito destroyer, Eucorethra underwoodi (Underwood) (= americana
Johannsen) is an important enemy of mosquito larvre in North America.
Other genera are Corethrella Coquillett, Cryophila Edwards, Moehlonyx Loew,
and Promochlonyx Edwards.
Family SIMULIIDJE Rondani 1856 (Sim'u-li'i-dre, from the Latin simulare,
to imitate, simulate). German, Kriebelmucken. Buffalo Gnats, Black
Flies, Turkey Gnats.
Minute, robust, hump-backed, black, orange, yellowish, gray, or sombercolored
gnats with short ll-segment.ed antennre; large round eyes, holoptic in
males, divided horizontally with upper facets larger; mouth parts for biting and
sucking with horny labella and four-segmented palpi; broad naked wings with
veins in the costal area prominent, others vestigial; alulre present; short legs
with tibial spurs, basal tarsal segment long and apical segment very small;
seven- to eight-segmented abdomen; genitalia hidden. The larvre are aquatic;
cylindrical with disk-like "sucker" fringed with hooks on the top of the head and
a similar structure at the posterior end; with three blood gills exserted from the
rectal cavity. The larvre spin cocoons, open in front and facing downstream, in
which to pupate. The pupre have two groups of prothoracic tracheal gills. The
adults emerge directly from the water and often swarm in the neighborhood of
swift fresh-water streams.
The females are voracious biters and bloodsuckers in some places and are one
of the vacationist's greatest tormentors in many parts of the temperate and
cooler regions. The eggs are deposited in great numbers on rocks and other