Bug FAQBomber fly
Heterostylum robustum · Order: Diptera · Family: Bombyliidae
Bomber flies have clear wings, a tan thorax, a gray-buff patterned abdomen and a long proboscis. The adults emerge in spring about ten days before bees and remain active for several weeks alongside their hosts.
Source: Wikipedia
How to recognize it
Adults show unclouded wings, a tan thorax, a gray and buff abdomen pattern and a long proboscis.
Source: Wikipedia
Is it a pest in the house?
As a bomber fly it targets bee and wasp nests rather than human structures or food stores.
Source: Wikipedia
Life cycle
The larvae develop through four molts before becoming adults. Larvae overwinter underground about 5 to 10 inches deep and later move upward to 2 to 3 inches below the surface.
Source: Wikipedia
When you see it
Adults emerge in spring roughly ten days earlier than bees and overlap with them for several weeks.
Source: Wikipedia
Where it comes from
Its native range includes southwestern Canada, the western U.S. and Mexico.
Source: Wikipedia
Lookalikes
Males have holoptic eyes (eyes meet at the top of the head) while females are dichoptic (eyes separated).
Source: Wikipedia
Where it is found in the US
Recorded in 16 of 51 states and DC. Most records: California, Arizona, Texas, Missouri, Oklahoma, New Mexico, Tennessee, Illinois.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
How can I tell male and female bomber flies apart?
Males have eyes that meet on the top of the head (holoptic) and females have separated eyes (dichoptic).
Source: Wikipedia
When do bomber flies appear?
Adults emerge in spring about ten days before bees and stay active for several weeks alongside them.
Source: Wikipedia
Same family (Bombyliidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Heterostylum_robustum
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.