Narrow-headed Marsh Fly
Helophilus (Helophilus) fasciatus Walker, 1849
Narrow-headed Marsh Fly in all of OhioRange
Where it is recorded
Season shown in 1 of Ohio's 88 counties. Explore Ohio
- No result yet (39)
- Recorded, too few records for a result (41)
- Recorded, season not shown (7)
- Season shown (1)
Counties as a table
| County | Records |
|---|---|
| Adams County | No qualifying records yet |
| Allen County | Recorded, too few records for a result |
| Ashland County | Recorded, too few records for a result |
| Ashtabula County | 21 · Recorded, season not shown |
| Athens County | No qualifying records yet |
| Auglaize County | No qualifying records yet |
| Belmont County | No qualifying records yet |
| Brown County | No qualifying records yet |
| Butler County | Recorded, too few records for a result |
| Carroll County | No qualifying records yet |
| Champaign County | Recorded, too few records for a result |
| Clark County | Recorded, too few records for a result |
| Clermont County | Recorded, too few records for a result |
| Clinton County | No qualifying records yet |
| Columbiana County | No qualifying records yet |
| Coshocton County | Recorded, too few records for a result |
| Crawford County | Recorded, too few records for a result |
| Cuyahoga County | 55 · Recorded, season not shown |
| Darke County | Recorded, too few records for a result |
| Defiance County | Recorded, too few records for a result |
| Delaware County | Recorded, too few records for a result |
| Erie County | Recorded, too few records for a result |
| Fairfield County | No qualifying records yet |
| Fayette County | Recorded, too few records for a result |
| Franklin County | 56 · Season shown |
| Fulton County | Recorded, too few records for a result |
| Gallia County | No qualifying records yet |
| Geauga County | Recorded, too few records for a result |
| Greene County | Recorded, too few records for a result |
| Guernsey County | No qualifying records yet |
| Hamilton County | 20 · Recorded, season not shown |
| Hancock County | Recorded, too few records for a result |
| Hardin County | Recorded, too few records for a result |
| Harrison County | No qualifying records yet |
| Henry County | Recorded, too few records for a result |
| Highland County | No qualifying records yet |
| Hocking County | Recorded, too few records for a result |
| Holmes County | No qualifying records yet |
| Huron County | No qualifying records yet |
| Jackson County | No qualifying records yet |
| Jefferson County | No qualifying records yet |
| Knox County | No qualifying records yet |
| Lake County | 26 · Recorded, season not shown |
| Lawrence County | No qualifying records yet |
| Licking County | Recorded, too few records for a result |
| Logan County | No qualifying records yet |
| Lorain County | Recorded, too few records for a result |
| Lucas County | 120 · Recorded, season not shown |
| Madison County | No qualifying records yet |
| Mahoning County | No qualifying records yet |
| Marion County | Recorded, too few records for a result |
| Medina County | Recorded, too few records for a result |
| Meigs County | No qualifying records yet |
| Mercer County | No qualifying records yet |
| Miami County | No qualifying records yet |
| Monroe County | No qualifying records yet |
| Montgomery County | 32 · Recorded, season not shown |
| Morgan County | No qualifying records yet |
| Morrow County | Recorded, too few records for a result |
| Muskingum County | No qualifying records yet |
| Noble County | No qualifying records yet |
| Ottawa County | Recorded, too few records for a result |
| Paulding County | Recorded, too few records for a result |
| Perry County | No qualifying records yet |
| Pickaway County | Recorded, too few records for a result |
| Pike County | No qualifying records yet |
| Portage County | Recorded, too few records for a result |
| Preble County | Recorded, too few records for a result |
| Putnam County | Recorded, too few records for a result |
| Richland County | Recorded, too few records for a result |
| Ross County | No qualifying records yet |
| Sandusky County | No qualifying records yet |
| Scioto County | No qualifying records yet |
| Seneca County | Recorded, too few records for a result |
| Shelby County | Recorded, too few records for a result |
| Stark County | Recorded, too few records for a result |
| Summit County | Recorded, too few records for a result |
| Trumbull County | Recorded, too few records for a result |
| Tuscarawas County | No qualifying records yet |
| Union County | No qualifying records yet |
| Van Wert County | No qualifying records yet |
| Vinton County | No qualifying records yet |
| Warren County | Recorded, too few records for a result |
| Washington County | No qualifying records yet |
| Wayne County | Recorded, too few records for a result |
| Williams County | Recorded, too few records for a result |
| Wood County | 24 · Recorded, season not shown |
| Wyandot County | Recorded, too few records for a result |
No mapped range from the range source used, the USGS Gap Analysis Project, which maps land vertebrates only.
Season
When it is recorded
In Ashtabula County
Not enough evidence
Records per week from 21 records in 8 of the 10 years from 2016 to 2025. Shows when people recorded it, not a season or how common it is.
Show as a table
| Week | Records of Narrow-headed Marsh Fly | Years recorded | Records of all species |
|---|---|---|---|
| Jan 4–10 | 0 | 0 | 11 |
| Jan 11–17 | 0 | 0 | 2 |
| Jan 18–24 | 0 | 0 | 7 |
| Jan 25–31 | 0 | 0 | 14 |
| Feb 1–7 | 0 | 0 | 4 |
| Feb 8–14 | 0 | 0 | 6 |
| Feb 15–21 | 0 | 0 | 4 |
| Feb 22–28 | 0 | 0 | 18 |
| Mar 1–7 | 0 | 0 | 10 |
| Mar 8–14 | 0 | 0 | 12 |
| Mar 15–21 | 0 | 0 | 32 |
| Mar 22–28 | 0 | 0 | 36 |
| Mar 29 – Apr 4 | 0 | 0 | 28 |
| Apr 5–11 | 1 | 1 | 80 |
| Apr 12–18 | 0 | 0 | 136 |
| Apr 19–25 | 3 | 2 | 175 |
| Apr 26 – May 2 | 2 | 2 | 244 |
| May 3–9 | 1 | 1 | 285 |
| May 10–16 | 2 | 1 | 238 |
| May 17–23 | 0 | 0 | 218 |
| May 24–30 | 0 | 0 | 359 |
| May 31 – Jun 6 | 2 | 1 | 407 |
| Jun 7–13 | 1 | 1 | 483 |
| Jun 14–20 | 0 | 0 | 627 |
| Jun 21–27 | 0 | 0 | 341 |
| Jun 28 – Jul 4 | 0 | 0 | 669 |
| Jul 5–11 | 0 | 0 | 565 |
| Jul 12–18 | 1 | 1 | 828 |
| Jul 19–25 | 2 | 2 | 1,038 |
| Jul 26 – Aug 1 | 0 | 0 | 623 |
| Aug 2–8 | 0 | 0 | 706 |
| Aug 9–15 | 0 | 0 | 686 |
| Aug 16–22 | 0 | 0 | 352 |
| Aug 23–29 | 0 | 0 | 611 |
| Aug 30 – Sep 5 | 0 | 0 | 653 |
| Sep 6–12 | 1 | 1 | 526 |
| Sep 13–19 | 2 | 1 | 310 |
| Sep 20–26 | 1 | 1 | 200 |
| Sep 27 – Oct 3 | 1 | 1 | 280 |
| Oct 4–10 | 0 | 0 | 276 |
| Oct 11–17 | 0 | 0 | 175 |
| Oct 18–24 | 1 | 1 | 175 |
| Oct 25–31 | 0 | 0 | 123 |
| Nov 1–7 | 0 | 0 | 46 |
| Nov 8–14 | 0 | 0 | 95 |
| Nov 15–21 | 0 | 0 | 26 |
| Nov 22–28 | 0 | 0 | 12 |
| Nov 29 – Dec 5 | 0 | 0 | 18 |
| Dec 6–12 | 0 | 0 | 21 |
| Dec 13–19 | 0 | 0 | 14 |
| Dec 20–26 | 0 | 0 | 7 |
| Dec 27 – Jan 2 | 0 | 0 | 10 |
Reported as an adult
No records here are marked as adults yet, so there is no adult season to show. One needs at least 20 records from 5 different years.
Reported as a larva
No records here are marked as larvae yet, so there is no larva season to show. One needs at least 20 records from 5 different years.
In Ohio
Late March to mid-June, middle week mid-April, and again late August to mid-October, middle week late September
Recorded in two separate seasons, each shown with its own early, middle and late weeks.
Records per week from 618 records in 9 of the 10 years from 2016 to 2025. Shows when people recorded it, not a season or how common it is.
Show as a table
| Week | Records of Narrow-headed Marsh Fly | Years recorded | Records of all species |
|---|---|---|---|
| Jan 4–10 | 0 | 0 | 6,211 |
| Jan 11–17 | 0 | 0 | 5,146 |
| Jan 18–24 | 0 | 0 | 4,645 |
| Jan 25–31 | 0 | 0 | 4,698 |
| Feb 1–7 | 0 | 0 | 6,023 |
| Feb 8–14 | 0 | 0 | 5,888 |
| Feb 15–21 | 0 | 0 | 5,436 |
| Feb 22–28 | 0 | 0 | 6,846 |
| Mar 1–7 | 1 | 1 | 8,321 |
| Mar 8–14 | 1 | 1 | 10,384 |
| Mar 15–21 | 4 | 3 | 12,620 |
| Mar 22–28 | 7 | 3 | 13,949 |
| Mar 29 – Apr 4 | 35 | 7 | 19,661 |
| Apr 5–11 | 66 | 7 | 26,860 |
| Apr 12–18 | 59 | 9 | 39,925 |
| Apr 19–25 | 39 | 7 | 41,623 |
| Apr 26 – May 2 | 24 | 8 | 56,391 |
| May 3–9 | 18 | 7 | 52,952 |
| May 10–16 | 24 | 8 | 53,785 |
| May 17–23 | 21 | 8 | 57,698 |
| May 24–30 | 23 | 7 | 54,651 |
| May 31 – Jun 6 | 31 | 7 | 53,099 |
| Jun 7–13 | 28 | 8 | 53,700 |
| Jun 14–20 | 17 | 6 | 56,625 |
| Jun 21–27 | 5 | 5 | 55,361 |
| Jun 28 – Jul 4 | 1 | 1 | 58,477 |
| Jul 5–11 | 1 | 1 | 61,336 |
| Jul 12–18 | 1 | 1 | 64,722 |
| Jul 19–25 | 3 | 3 | 69,753 |
| Jul 26 – Aug 1 | 0 | 0 | 59,416 |
| Aug 2–8 | 1 | 1 | 59,712 |
| Aug 9–15 | 2 | 1 | 55,994 |
| Aug 16–22 | 2 | 2 | 54,328 |
| Aug 23–29 | 2 | 2 | 51,772 |
| Aug 30 – Sep 5 | 8 | 5 | 57,167 |
| Sep 6–12 | 29 | 8 | 59,075 |
| Sep 13–19 | 26 | 7 | 54,543 |
| Sep 20–26 | 25 | 9 | 45,860 |
| Sep 27 – Oct 3 | 34 | 9 | 43,180 |
| Oct 4–10 | 39 | 8 | 37,841 |
| Oct 11–17 | 21 | 8 | 30,824 |
| Oct 18–24 | 11 | 5 | 21,156 |
| Oct 25–31 | 6 | 4 | 19,021 |
| Nov 1–7 | 2 | 2 | 14,172 |
| Nov 8–14 | 1 | 1 | 12,621 |
| Nov 15–21 | 0 | 0 | 7,965 |
| Nov 22–28 | 0 | 0 | 8,136 |
| Nov 29 – Dec 5 | 0 | 0 | 6,083 |
| Dec 6–12 | 0 | 0 | 6,004 |
| Dec 13–19 | 0 | 0 | 5,423 |
| Dec 20–26 | 0 | 0 | 5,661 |
| Dec 27 – Jan 2 | 0 | 0 | 8,459 |
Reported as an adult
Usually reported as an adult late March to early June, middle week mid-April, and again early September to mid-October, middle week mid-September.
Reported as a larva
No records here are marked as larvae yet, so there is no larva season to show. One needs at least 20 records from 5 different years.
What these results show
These results show when people recorded a species, not when or where it occurs. Missing weeks and low counts do not mean absence or scarcity, and counts are not abundance. Contributed records reflect where, when and what people chose to observe.
Identification
How to identify it
Often confused with
- Transverse-banded Flower Fly Eristalis (Eoseristalis) transversa52 identifications worldwide named one where the other was meant
- Western Honey Bee Apis mellifera16 identifications worldwide named one where the other was meant
From iNaturalist’s similar-species counts, refreshed monthly: confusions in Ohio first, then worldwide. Only species with an Ohio result are listed.
Months not reported
- Jan: no record
- Feb: no record
- Mar: recorded
- Apr: recorded
- May: recorded
- Jun: recorded
- Jul: recorded
- Aug: recorded
- Sep: recorded
- Oct: recorded
- Nov: recorded
- Dec: no record
Not reported in Ohio in December to February, 2016 to 2025.
Land cover where it is recorded
| Land cover | Its recordsAll Ohio records |
|---|---|
| Developed | 42%49% |
| Forest | 33%31% |
| Farmland | 11%11% |
| Wetland | 10%5% |
| Grassland and shrub | 2%0.9% |
| Open water | 1%3% |
From 294 records placed within 100 m, beside all Ohio records placed the same way. People record where they go, so this shows where records come from, not where the species lives. Land cover: USGS Annual NLCD, 2025 (opens in a new tab)
Sources
Where these results come from
- Records from iNaturalist research-grade observations and expert-identified GBIF datasets, CC0, CC BY and CC BY-NC. Sources
- Seasons use the published method and its evidence thresholds. Methods
- See it on iNaturalist (opens in a new tab)OpenPhenology is independent and not affiliated with iNaturalist.
Records behind the Ohio result
618 records from 2 datasets.
- iNaturalist Research-grade Observations (opens in a new tab) · iNaturalist.org · 609 recordsiNaturalist contributors, iNaturalist (2026). iNaturalist Research-grade Observations. iNaturalist.org. Occurrence dataset https://doi.org/10.15468/ab3s5x accessed via GBIF.org on 2026-11-13.
- iNaturalist observations (opens in a new tab) · iNaturalist.org · 9 recordsiNaturalist. Available from https://www.inaturalist.org. Accessed 2026-11-13
To cite: the GBIF download doi:10.15468/dl.y2jkt8 (opens in a new tab).
A spreadsheet (CSV) with a link to each record, on iNaturalist or GBIF. Records whose location was hidden by the observer or the source are counted but not linked.