Bug FAQGarden March Fly
Bibio hortulanus · Order: Diptera · Family: Bibionidae
Garden March Flies are about 6.5 to 8.5 mm long with wings around 9.5 mm long. Males are all black, while females have an orange-red thorax and abdomen with black sides. Adults appear from mid-March to mid-June, feeding on Apiaceae flowers; larvae live in soil eating humus, dead leaves and grass roots.
Source: Wikipedia
How to recognize it
Males are completely black and slightly smaller than females. Females have orange-red dorsal thorax and abdomen, with black prothorax and sides.
Source: Wikipedia
Size
Body length ranges from about 6.5 to 8.5 mm (0.26 to 0.33 in). Wing length is roughly 9.5 mm.
Source: Wikipedia
Where it lives
They are found on woodland edges, meadows, flowering crops and hedgerows.
Source: Wikipedia
What it eats
Adults mainly feed on flowers of the Apiaceae family. Larvae live in soil, eating humus, dead leaves and the roots of grasses (Poaceae).
Source: Wikipedia
Life cycle
Adults are present from mid-March to mid-June.
Source: Wikipedia
When you see it
The flight period spans mid-March through mid-June.
Source: Wikipedia
Where it comes from
The species occurs throughout most of Europe, as well as North Africa and the Middle East.
Source: Wikipedia
Lookalikes
It resembles Bibio pomonae, which can be told apart by its red-colored femurs.
Source: Wikipedia
Where it is found in the US
Recorded in 1 of 51 states and DC. Most records: Pennsylvania.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
More photos
Questions people ask
When can I expect to see Garden March Flies?
Adults are active from mid-March to mid-June.
Source: Wikipedia
How can I tell male and female Garden March Flies apart?
Males are all black and a bit smaller, while females have orange-red backs with black sides.
Source: Wikipedia
Where do these flies usually live?
They prefer woodland margins, meadows, flowering crops and hedgerows.
Source: Wikipedia
What do Garden March Flies eat?
Adults feed on Apiaceae flowers; larvae eat soil humus, dead leaves and grass roots.
Source: Wikipedia
Same family (Bibionidae)
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Sources
- Wikipedia: https://en.wikipedia.org/wiki/Bibio_hortulanus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.