Atomosia

Small robber flies with long, stalked antennae, like Cerotainia. One of the most common, Atomosia puella, often perches upside down.

Atomosia glabrata

Small. Fore and mid femora darkened on dorsal surface. Hind femur with broad, black ring on the apical half. Tibiae mostly yellow with black on dorsum. Scutellum (structure on rear of thorax) with two long, white, lateral hairs. White mystax. Shorter antennae than A. arkansensis.

Size: 6-8 mm

Range: Eastern and Midwestern U.S.

FL Range: Alachua County

FL Season: September

Atomosia puella

Dark overall. Dark legs. Mystax white or yellow. White tomentose (microscopic hairs) on face. Similar to A. melanopogon, though males of that species have black mystax and black tomentose on face. Females of both A. puella and A. melanopogon have a white mystax with white tomentose on the face. Palpus white setose on A. puella. (black setose on A. melanopogon.) R5 vein cell open along wing margin. Associated with bark of trees and logs, and often perches facing down.

Size: 5.1-8 mm

Range: Eastern and Midwestern U.S.

FL Range: Panhandle and North Florida

FL Season: May-September

Atomosia rufipes

Yellowish or reddish legs with dark spot at apex of hind tibia. Larger than A. sayii. Cell R5 on wing broadly open at wing margin. Perches on leaves.

Size: 8-10 mm

Range: Eastern and Midwestern U.S.

FL Range: Throughout (Escambia, Duval, Alachua, Manatee, and Sarasota Counties).

FL Season: June-August

Atomosia sayii

Yellow legs without dark at apex. Golden pile (tiny hairs) on scutum (top of thorax) makes it appear golden. Smaller than A. rufipes. Cell R5 on wing closed or nearly closed at wing margin. Found on tips of twigs or resting on leaves.

Size: 6-8 mm

Range: Eastern and Midwestern U.S.

FL Range: Panhandle and north Florida. Bromley (1950) lists a Pasco County record.

FL Season: June-August

Atomosia melanopogon

Male with black mystax, female with white mystax. Male with black tomentose (microscopic hairs) on face. Female with white tomentose on face. Males have black mystax and black tomentose on face. Females of both A. puella and A. melanopogon have a white mystax with white tomentose on the face. Palpus black setose on A. melanopogon. (white setose on A. puella.) Closed R5 vein cell on wing (see these images from Gayle and Jeanell Strickland).

Size: 6-8 mm

Range: Southern U.S. east to Mississippi. South to Honduras.

Season: April-September

Atomosia arkansensis

Femora mostly black with base and apex yellow. Tibiae yellow or reddish yellow with dark apices. On antenna, flagellum 3.2 times as long as scape. Antennae longer than on A. glabrata.

Size: 5-7 mm (excluding antennae)

Range: Arkansas, Louisiana

Season: June

Photos by Gayle and Jeanell Strickland

Atomosia mucida

Yellow base of antennae. Dense, silvery hair (setae) on thorax. Yellow legs.

Size: 7-10 mm

Range: Southwestern U.S. but also one Arkansas locality.

References:

Barnes, J. K. (2008). The genus Atomosia Macquart (Diptera: Asilidae) in North America north of Mexico. Proceedings of the Entomological Society of Washington, 110(3), 701-732.

Bromley, S. W. (1950). Florida Asilidae (Diptera) with description of one new species. Annals of the Entomological Society of America, 43(2), 227-239.