Plants and Animals

Neohermes concolor A fishfly

Key Characteristics

Neohermes concolor adults are 25-40mm in length with forewing length averaging 28-35 mm. Long, thin antennae range from one-half to three-quarters the length of forewing and are formed of beadlike rounded segments (moniliform), with each segment marked by a ring of erect hairs in the male. Wings have a grayish tint, the forewings and outer edge of the hindwings being heavily marked with black blotches perpendicular to the direction of the veins. The head and body are a mottled gray to brown color. Compound eyes and mandibles are prominent and three well-developed ocelli can be seen. Mature Neohermes larvae are typically over 30mm in length, yellowish-brown to brown in overall coloration, with squarish head and thorax sclerotized dorsally in dark brown patterns. Abdominal segments 1-8 feature two very long and thick lateral filaments. Mandibles are prominent and dark brown, and antennae have five segments. Neohermes concolor larvae are primarily distinguished from other Neohermes species by the position of the eighth abdominal spiracles, certain genital characteristics, and the arrangement of the setae on the anal plate of males.

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: GNR - Not ranked
State Rank: SH - Possibly extirpated


CountyNumber of OccurrencesYear Last Observed

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Neohermes concolor larvae are found in seeps and springs, as well as small, low-gradient woodland streams (Bowles and Mathis 1992).

Natural Community Types

  • Headwater stream (1st-2nd order), riffle
  • Headwater stream (1st-2nd order), pool
  • Headwater stream (1st-2nd order), run

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Fishfly and dobsonsly larvae (or hellgrammites) require clear, high water quality streams (FLOW 2003, Williams and Feltmate 1992). Construction projects, dredging, deforestation and other activities that result in siltation will negatively impact this species. Minimizing point and non-point source pollution is a management priority for this and many other sensitive aquatic insects. As fishfly adults breed and deposit eggs on woody vegetation which overhangs streams, and pupae often utilize rotten wood along banks (Williams and Feltmate 1992), such habitat features should be left undisturbed. Hellgrammites are commonly collected as fish bait, both commercially and by individual anglers (New 1995). In one West Virginia river system, for example, over 740,000 harvested specimens were documented in a year (Nielson and Orth 1988). Further research is needed to determine the impacts of sportfishing on fishfly populations.

Active Period

Breeding from fourth week of April to second week of August

Survey Methods

Adults can be surveyed using light traps, while the aquatic larvae are generally collected with d-frame or kick nets or by searching individual rocks (New 1998).

D-frame net, dip net

Survey Period: From fourth week of April to second week of August

Survey Method Comment: Larvae


Survey References

  • New, T.R. 1998. Invertebrate Surveys for Conservation. Oxford University Press, New York. 240pp.

Technical References

  • Arnold, D.C. and W.A. Drew. 1987. A Preliminary Survey of the Megaloptera of Oklahoma. Proceedings of the Oklahoma Academy of Science 67: 23-26.
  • Bowles, D.E. and M.A. Mathis. 1992. Variation in the terminalia of Neohermes concolor with a key to males of Neohermes in eastern North America (Megaloptera: Corydalidae: Chauliodinae). Insecta Mundi 6(3-4): 145-9.
  • Flint, O.S., Jr. 1965. The Genus Neohermes (Megaloptera: Corydalidae). Psyche 72: 255-63.
  • FLOW. 2003. A Snapshot: The State of the Lower Olentangy River Watershed in 2001. Lower Olentangy River Watershed Inventory.
  • Merritt, R.W. and K.W. Cummins. 1996. An introduction to the aquatic insects of North America, 3rd ed. Kendall/Hunt Publishing Company, Dubuque. 862pp.
  • New, T.R. 1995. An Introduction to Invertebrate Conservation Biology. Oxford University Press, New York. 194 pp.
  • Nielson, L.J. and D.J. Orth. 1988. The hellgrammite-crayfish bait industry of the New River and its tributaries, West Virginia. North American Journal of Fisheries Management 8(3): 317-24.
  • Tarter, D.C., W.D. Watkins and D.A. Etnier. 1979. Larval description and habitat notes of the fishfly Neohermes concolor (Davis) (Megaloptera: Corydalidae). Entomological News 90(1): 29-32.
  • Williams, D.D. and B.W. Feltmate. 1992. Aquatic Insects. C.A.B. International, Wallingford, U.K. 358pp.