The hover flies are a large group of
generally beneficial insects. Their coloring and movements
of most species mimic bees or wasps -- they are either
stout-bodied and covered with hair, resembling a bumble bee,
or boldly patterned with yellow, orange and black,
resembling wasps or honey bees. Some species even go so far
as to wave their front legs in front of their face to mimic
the jointed antennae of the potter wasps.
Adult hover
flies can generally be found hovering in midair or feeding
at flower blossoms. They eat only nectar and pollen.
However, their larvae can be rapacious predators of aphids,
thrips, and mites, or parasitic in the nests of ants or
solitary bees. Still other larvae scavenge in soil or
decaying plant material or eat living plants. Some are
aquatic.
Most hover flies are between 5-20 mm long,
brightly colored in yellow and black, and have large
compound eyes that nearly cover the head. One rule of thumb
for identifying hover fly gender is, if the eyes meet at the
top of the head, it's a male specimen. Each wing has a
characteristic fold, or "false vein" which can be visible to
the naked eye - it is located anterior to the first large
vein that runs all the way to the outer margin of the wing.
Of course, being true flies, they have only one pair of
wings, plus the characteristic halteres, or bulb-like organs
that evolved from the second pair of flying wings. In
Syrphid flies, however, the halteres are fairly
inconspicuous.
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