''Orthonevra robusta'', the short-horned mucksucker, is a rare species of

syrphid fly Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while ...

, located in the Western United States. It was described by

Raymond Corbett Shannon Raymond Corbett Shannon (4 October 1894 – 7 March 1945) was an American entomologist who specialised in Diptera and medical entomology. Life and career Shannon was born in Washington D.C. He was orphaned as a child. His studies at Cornell Unive ...

in 1916. Hoverflies are able to be motionless while in flight.They are also called flower flies, for they are commonly found around and on flowers from which they get both energy-giving

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

and protein rich

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

. Larvae for this genus are of the rat-tailed type. ''O. robusta'' larvae have not been described.

Description

For terms see Morphology of Diptera. ;Size Length, ;Head The ocellar triangle and frons are bronzy green, with conspicuous, pale brownish pile. The frons in the female is rather smooth, transversely rugose, and interrupted medianly by a very shallow longitudinal furrow. The pile of the frons is short, yellowish brown.The face is greenish black, with short white pile. In profile the face is rather gently excavated while the mouth margin reaches forward as far as antennal prominence. There is a distinct whitish pollinose band extending across to the eyes and below this. The face is broadly, faintly rugulose.The antennae are blackish, and reddish on the under side of the third joint, which is a little longer than broad. The arista is dark, very minutely pubescent and a little longer than antennae. ;Thorax The thorax has a very short, pale brownish pile. The mesonotum has two median, very faint stripes. In the female, stripes on the mesonotum are more distinct, silvery green. ;Wings Wings slightly smoky. The squamae are whitish and halteres are yellowish. ;Legs The first tarsal joint of the hind legs are somewhat swollen ;Abdomen The center of the abdomen is sub

opaque Opacity or opaque may refer to: * Impediments to (especially, visible) light: ** Opacities, absorption coefficients ** Opacity (optics), property or degree of blocking the transmission of light * Metaphors derived from literal optics: ** In lingui ...

, shining at the sides. The hypopygium is rather large, with abundant, short, whitish pile In the female the abdomen is nearly as broad as long.

Distribution

British Columbia, Manitoba, Washington, Oregon, Nebraska and California

References

Hoverflies Brachyopini Taxa named by Raymond Corbett Shannon Insects described in 1916 Diptera of North America {{Brachyopini-stub