Proctacanthus fulviventris

The combination of large size (25–30 mm), bright yellow beard, black femora with red tibiae, and reddish abdominal terga distinguishes this species from other eastern North American Proctacanthus. Dark coloration with light brown wings separates it from P. milbertii, which has more extensive yellow markings and occurs across much of the U.S. rather than being Florida-near endemic. The specific epithet fulviventris (yellow-bellied) and generic name Proctacanthus (spiny-butt) both reference diagnostic features.

Large robust robber fly, 25–30 mm in length. Bright yellow mystax (dense beard of bristles on face). Black femora contrasting with red tibiae. Reddish abdominal terga. Dark overall coloration with light brown wings.

Sand pine scrub habitat with white-sand substrates. Found along sandy 2-tracks and open sandy areas within pine scrub. Requires loose sandy soil for oviposition.

Florida near-endemic, extending minimally into southern Georgia. Documented from Levy County and Dixie County in north Florida.

Females oviposit by inserting abdomen deeply into loose sand. After withdrawal, female sweeps abdomen tip back and forth over the hole, presumably to cover and hide the eggs. Larval stages unknown but presumed to feed on soil insects, roots, and decaying organic matter based on congeneric patterns in Proctacanthus.

Perches on substrates in open sandy areas. Oviposition observed in loose sand with subsequent covering behavior. Rapid flight when disturbed.

Predatory robber fly, likely contributing to regulation of insect populations in sand pine scrub ecosystems. Specific prey unknown but presumed to include various flying insects typical of Asilidae.

• Proctacanthus milbertiiLarger geographic range across much of the U.S., late season species, loves butterflies (though grasshoppers comprise 94% of prey), more extensive yellow markings rather than dark coloration with yellow beard only
• Promachus speciesSimilar large size and robust build in Asilinae, but distinguished by tiger-striped abdominal patterning in P. hinei, P. rufipes, and P. vertebratus versus reddish abdominal terga in P. fulviventris

• robber fly
• Asilidae
• Florida endemic
• sand pine scrub
• large predatory fly

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Asilidae | Beetles In The Bush | Page 2
• Magnificently Monstrous Muscomorphs | Beetles In The Bush