Nicocles

The three eastern species are very similar, but can be distinguished by leg color and the extent of smokey shading on the wings.

With females nearby, two males hovered up and down while undulating their abdomens causing them to ‘flash.’

Paul Bedell took me to his Nicocles pictus spot where we got to see several males displaying. These males would undulate their abdomens, causing it to “flash.” Combined with the smokey bands on the wings, one can see from this series how a nearby robber fly might perceive it.

Nicocles engelhardti

Hind femora red. Other femora black. Wings entirely smokey, slightly lighter on apical third. Halteres yellow.

Size: 7-9 mm

Range: Southeast (North Carolina to Florida)

FL Range: Panhandle

FL Season: April, October-November

Nicocles pictus

All femora entirely dark red. Wings with smokey dark spots near the wing veins on apical two-thirds. Abdomen pollinose laterally except on fifth segment.

Size: 10-12 mm

Range: Eastern U.S.

FL Range: Unknown

Season: January to April then again October-November outside of Florida.

Nicocles politus

Femora black except at apex. Apical two-thirds of wings dusky. Halteres brown. Fall flight season.

Size: 8-10 mm

Range: Eastern U.S. (Massachusetts to Florida)

FL Range: Panhandle and North Florida (Santa Rosa, Franklin, Nassau, Duval, Alachua, Marion)

FL Season: October-December

First two images by Giff Beaton (iNaturalist, iNaturalist, CC BY-NC), second two by Royal Tyler (iNaturalist, CC BY-NC-SA)

Nicocles reinhardi

Apical third of middle and apical half of fore femora black. Abdomen thinly pollinose throughout. Dark on wings only along veins – otherwise clear-winged.

Size: 9 mm

Range: Texas

References:

Wilcox, J. (1946): New Nicocles with a key to the species (Diptera, Asilidae). Bulletin of the Brooklyn Entomological Society 40(1945): 161-165; New York – Lancaster.