Bug FAQTwo-lined Swamp Fly
Anasimyia bilinearis · Order: Diptera · Family: Syrphidae
Adult two-lined swamp flies visit flowers to drink nectar and collect pollen for protein. The larvae are rat-tailed types that live in water. This species is uncommon but can be seen across North America.
Source: Wikipedia
How to recognize it
Adults are called flower flies because they are often seen on flowers.
Source: Wikipedia
Where it lives
Larvae of this genus are rat-tailed and develop in aquatic habitats.
Source: Wikipedia
What it eats
Adults obtain energy from nectar and protein from pollen on flowers.
Source: Wikipedia
Life cycle
The immature stage is a rat-tailed larva that lives in water.
Source: Wikipedia
Where it is found in the US
Recorded in 23 of 51 states and DC. Most records: Massachusetts, Minnesota, Maine, Wisconsin, New York, Vermont, Ohio, Michigan.
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
What do adult two-lined swamp flies eat?
They feed on flower nectar for energy and on pollen for protein.
Source: Wikipedia
Where do the larvae of the two-lined swamp fly live?
The larvae are rat-tailed and live in aquatic environments.
Source: Wikipedia
Is the two-lined swamp fly found in my area?
It is an uncommon species that occurs throughout North America.
Source: Wikipedia
Same family (Syrphidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Anasimyia_bilinearis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.