Anthrax georgicus

Adults resemble small, furry bees with a single pair of wings (diagnostic for Diptera). Distinguished from true bees by wing venation and halteres. Larvae are legless, maggot-like, and attach externally to host insects. Separated from congeneric species by specific wing patterns and geographic distribution; A. georgicus is the primary Nearctic species parasitizing tiger beetles.

Open sandy or clay soils where tiger beetle larvae construct burrows; often found in prairies, sand prairies, barren ground, and other areas with exposed soil suitable for ground-nesting insects.

Eastern and central United States, including Missouri, Virginia, and surrounding regions. Records extend from the Mississippi lowlands to the Atlantic coastal plain.

Adults active in spring (March–May), coinciding with activity periods of host tiger beetle larvae.

Larval stage: parasitoid, feeding on tiger beetle larvae (Cicindelidae), specifically species in genera Cicindela, Cicindelidia, Ellipsoptera, and Tetracha. Adult stage: nectar from flowers (pollen collection incidental).

• Cicindela scutellaris - larval hostdocumented by Shelford (1913)
• Cicindelidia obsoleta - larval hostdocumented by Hamilton (1925)
• Cicindela hirticollis - larval hostdocumented by Bram and Knisley (1982)
• Cicindela tranquebarica - larval hostdocumented by Bram and Knisley (1982)
• Cicindelidia punctulata - larval hostdocumented by Bram and Knisley (1982)
• Ellipsoptera marginata - larval hostdocumented by Bram and Knisley (1982)
• Tetracha virginica - larval hostdocumented by MacRae and Ernst (2021)

Complete metamorphosis with four stages: egg, larva, pupa, adult. Females deposit eggs near or at entrances of tiger beetle larval burrows. First-instar larvae attach externally to host larvae, typically at the thorax or fifth abdominal segment. Larvae remain attached through host development, accelerating consumption as host approaches maturity. Pupation occurs in soil after host death and consumption.

Adult females locate host burrows by flying backward and downward while thrusting the abdomen forward until touching the substrate near burrow entrances. Larvae are ectoparasitoids, attaching to host skin and feeding on host tissues and hemolymph.

Parasitoid regulating populations of tiger beetles. Adult pollination services incidental through nectar feeding and pollen transport.

Subject of entomological research on parasitoid-host relationships and tiger beetle conservation biology. No direct economic impact on agriculture or human health.

• Anthrax gideonAlso parasitizes tiger beetles, but occurs in Central and South America (Costa Rica, Brazil) rather than North America
• Bombylius majorSimilar adult appearance as bee fly, but larger, with different wing pattern; parasitizes solitary bees rather than tiger beetles
• Systoechus spp.Similar bee fly morphology, but generally active in fall rather than spring; host relationships differ

Previously confused with Anthrax analis; older literature under that name refers to this species. Often mistaken for bees by casual observers due to convergent morphology.

• parasitoid
• tiger beetle
• bee fly
• Cicindelidae
• Bombyliidae
• spring-active
• ground-nesting insects
• ectoparasite
• biological control
• sandy habitats

• BugGuide
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• Ground nesting bees beware of the bee fly: Bombyliidae — Bug of the Week
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• My Publications | Beetles In The Bush
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