Clubbed Mydas Fly

Mydas clavatus · Order: Diptera · Family: Mydidae

No source yet on danger. We have no source yet on whether it bites, stings or damages anything.
Clubbed Mydas Fly
Photo: Steven Bodzin, CC BY

Clubbed mydas flies are large, black insects about 2.5 to 3 cm long with a wingspan over 5 cm and a bright orange-red spot on the underside of the second abdominal segment. They live in many open habitats such as woodlands, fields, gardens and meadows across eastern North America, and adults feed on pollen and nectar from a variety of flowers.

Source: Wikipedia

How to recognize it

The species gets its name from its club-shaped antennae, a trait common to all Mydas flies.

Source: Wikipedia

Size

Adults are 25 to 30 mm long and can have a wingspan exceeding 50 mm.

Source: Wikipedia

Where it lives

They are found in deciduous woodlands, fields, meadows, gardens and similar environments.

Source: Wikipedia

What it eats

Adults visit flowers such as milkweed, spirea, monarda, and verbena for pollen and nectar. Larvae are predators of scarab beetle larvae that live in dead wood.

Source: Wikipedia

Life cycle

Females lay single eggs in soil or rotting wood. Larvae develop in standing or fallen trees with extensive heart rot, feeding on scarab beetle larvae.

Source: Wikipedia

When you see it

Adults are active in mid-summer.

Source: Wikipedia

Where it comes from

The species is native to temperate eastern North America.

Source: Wikipedia

Lookalikes

They mimic spider wasps and move boldly as a result.

Source: Wikipedia

Where it is found in the US

Recorded in 35 of 51 states and DC. Most records: Texas, Ohio, Virginia, Florida, North Carolina, Illinois, Maryland, Michigan.

Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: native in North America; native in Canada; native in United States. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

More photos

Clubbed Mydas Fly photo 3
Photo: Tom Field, CC BY
Clubbed Mydas Fly photo 4
Photo: Brandon McCracken, CC BY
Clubbed Mydas Fly photo 5
Photo: David Stutzman, CC BY
Clubbed Mydas Fly photo 6
Photo: Zachary Dankowicz, CC BY

Sources

  • Wikipedia: https://en.wikipedia.org/wiki/Mydas_clavatus

Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia

Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.

How this page works

This is one bug's fact sheet. The colored box at the top says whether it is dangerous. Sections below cover how to recognize it, whether it is a pest, and how to deal with it. The US map shows which states have records; tap a state to see other bugs there.

Every fact on Bug FAQ comes from a named source (university extension sites, government agencies, GBIF, iNaturalist, Wikipedia). The source is linked next to each section. If we have no source for something, we leave it out.