Sand Fly-Hawk Robber Fly
Head: Entirely with white pile and hair. Mustache (mystax) white, may have a few black bristles.
Antenna: Black, appears Y-shaped. Base (1st segment) thick, 2nd segment has a long bristle. 1 and 2 combined are same length as last segment.
Thorax: Brownish; no black stripes. Shoulders (humeri) slightly grayish, and along lower border of segment. Segment 2 (scutellum) grayish. Thorax sides same, or slightly lighter in female. May have some grayish pile.
Wings: Wings transparent (hyaline), outer edge (costal) more yellowish on female. Veins brown.
Legs: Thighs (femora) black with scattered whitish pile. Shins (tibiae) red to pale orange, black tips on female and pale yellow, black tips on male. Hind shin about ½ red-orange or yellow. Front and mid foot mixed reddish and black with black bristles. Hind foot black.
Abdomen:Male: Segment 1 gray, segments 2, 3 and 4 black with sides and lower margin white. Segments 5 and 6 white. Large bulbous tip black. Underside white with some long white hair.
Female: Segment 1 gray, segments 2 to 6 black with sides and lower margin white. Underside brownish. Ovipositor black, considered short, cone-shaped.
Similar Species: Both the male and female Efferia aestuans have an obvious pair of black stripes on thorax and bright yellow toes (foot pads or pulvilli). Male has 3 white segments (not 2) near abdomen tip. Female has very long, thin ovipositor (not cone-shaped).
Size: 16 to 19 mm.
Habitat: Prefers sandy beaches with dune grass. Sandy meadows near forest edge. In Ontario, only found along Lake Erie and Huron shoreline and inland.
Food: Grasshoppers, Flies and Wasps. Will also eat other Robber Flies.
Flight Time: June and July
Life Cycle: Females lay eggs (about 20) in sand. Larvae food is unknown, but have been found in soils infested with white grubs. Pupate in late May and emerge as adults in June and July. Adults frequently found flattened and quiet, blending in with the warm sand in cooler weather. Prey usually captured in mid-air. Males tackle females for mating in mid-air and then drop to the ground.
Comments: Essex County – Point Pelee National Park; Kent County – Rondeau Provincial Park; Lambton County.
DNA samples submitted to GenBank from Canada (B.C.) suppressed. Other samples from U.S.A. that have a GenBank reference number are missing at GenBank. GenBank has no taxonomic number for Efferia albibarbis.
For information on synonyms, references and type specimens see next page