Bug FAQSaw-combed Fishfly
Nigronia serricornis · Order: Megaloptera · Family: Corydalidae
Also called: Serrate Dark Fishfly
The saw-combed fishfly is also called a hellgrammite or fishfly. It lives in woodland streams across the eastern United States, from Florida up to Ontario and west toward the Rocky Mountains. Its larvae hunt small aquatic insects and crustaceans for up to three years before emerging as adults.
Source: Wikipedia
How to recognize it
Common names include hellgrammites, fishflies, and saw-combed fishflies.
Source: Wikipedia
Where it lives
It is a frequent resident of woodland streams in North America.
Source: Wikipedia
What it eats
Their diet changes with the seasons and even from month to month.
Source: Wikipedia
Life cycle
The species goes through egg, larva, pupa, and adult stages over about three weeks, but the larval stage can last up to three years.
Source: Wikipedia
Where it comes from
Its range covers the eastern United States, extending north to Ontario and west to the Rocky Mountains.
Source: Wikipedia
Lookalikes
The only similar North American species is Nigronia fasciatus, which looks much the same.
Source: Wikipedia
Where it is found in the US
Recorded in 32 of 51 states and DC. Most records: Vermont, Pennsylvania, New York, Virginia, Connecticut, Michigan, Massachusetts, Maryland.
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 other names does the saw-combed fishfly have?
It is also known as a hellgrammite or fishfly.
Source: Wikipedia
Where can I find saw-combed fishflies?
They live in woodland streams throughout the eastern United States, from Florida up to Ontario and west toward the Rockies.
Source: Wikipedia
How long do the larvae live?
Larvae can remain in the water for up to three years before becoming adults.
Source: Wikipedia
Same family (Corydalidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Nigronia_serricornis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.