Holopogon

Like Cerotainia, these are also tiny twig-perchers, but they have shorter antennae. There are two species of Holopogon verified from Florida which can be distinguished by the color of the abdominal segments and their hairs. There is considerable gray on the sides of the abdomen in H. guttulus, but the base color is mostly black in H. phaeonotus. Identification of other species of Holopogon relies of tibia and femora shape, relative leg bristle length, wing color, and the color of the stripes on the thorax.

Holopogon guttulus

Side of the abdomen is gray for the first few segments. Abdominal tergite 1 (closest to the thorax) has dense gray hairs on the sides, and abdominal segments 2-4 are mostly gray (female) or brown (male) on the sides.

Size: 8 mm

Range: Eastern U.S. south of NJ

FL Season: April-May

FL Range: Throughout south to Highlands County

The sides of the abdomen are pale and gray on H. guttulus. 19. H. guttulus female. 20 H. guttulus male. 21. H. phaeonotus female. Figures from Martin (1959).

Holopogon phaeonotus

The side of the first abdominal segment may have dense brown hairs, but the abdomen is mostly shining black. Abdominal tergite 1 (closest to the thorax) has hairs on the sides that are either thin or dense brown. Abdominal segment 2-3 and sometimes 4 may be narrowly brown, but abdominal segments 3-4 are usually entirely shining black.

The wings are light brown. Hind tibiae are club-shaped with a diameter greater than the hind femora.

Size: 8 mm

Range: Eastern U.S. and Canada

FL Season: Late March-May

FL Range: South to Orlando

Holopogon vockerothi

This species has been recorded from Mitchell County in southern Georgia (Martin, 1959), and there are specimens from Archbold Biological Station in Highlands County, but I have not verified these. It is very similar to H. phaeonotus, but the wings are clear and broader.

H. phaeonotus and H. oriens have a median brown stripe on the thorax bordered by paler stripes. In H. vockerothi, the median brown stripe on the thorax is bordered by black stripes.

Size: 7 mm

Range: Eastern U.S. and Canada

FL Season: April

These photos by Mike Reese may be H. vockerothi.

Holopogon oriens

This species has been recorded in Georgia. It is very similar to H. phaeonotus, but the tibias are relatively uniform in width as opposed to being club-shaped as in H. phaeonotus. The tibias are similar in diameter to the hind femora.

Size: 6 mm

Range: Eastern U.S.

References:

Back, E. A. (1909). The robber-flies of America, north of Mexico, belonging to the subfamilies Leptogastrinae and Dasypogoninae. Transactions of the American Entomological Society (1890-), 35(2/3), 137-400.

Martin, C. H. (1959). The Holopogon complex of North America, excluding Mexico, with the descriptions of a new genus and a new subgenus (Diptera, Asilidae). American Museum novitates; no. 1980.

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