Nigronia fasciata

Banded Fishfly
Nigronia fasciata

Note: Although present in Ontario, these photos of a female were taken in New Brunswick.

Head: Dark brown with some reddish-brown streaks at back of head. Simple eyes (ocelli) smaller. Cheeks and underside on mouth brick-red. Mandibles brown, base yellowish.
Antenna: Black, feathered (flabellate) on both sides on male, knife-like (serrate) on female.
Thorax: Neck (pronotum) as wide as long; dark brown with some reddish-brown streaks and darker spots; rest of thorax dark brown.
Wings: Wings are dark brown with an evenly wide white stripe mid wing, and white spots near wing tip. Hind wings dark brown; base has a large rounded white spot, a wide mid wing white stripe, and white spots near wing tip. Male brighter colored.
Legs: Brown, feet darker.
Abdomen: Abdomen black, with lighter patterned areas.

Main ID: Evenly wide white stripe across middle of front wings.

Similar Species: N. serricornis has a much narrower and very uneven mid-wing white stripe; no stripe on hind wing.

Size: 30 to 40 mm. Larva 26 to 33 mm.

Flight Time: June

Habitat: Small streams with sandy bottoms and few rocks; and good water quality.

Food: Larvae feed on smaller aquatic animals. Adults may feed on nectar – drink sugar water in the lab.

Life Cycle: Females lay large egg masses in the afternoon from May to early June on the underside of leaves of branches over-hanging streams. After hatching (14 days), larvae drop into the water and feed on Isopoda (most), Caddisflies (2nd most), Diptera, Ephemeroptera, Megaloptera, and will resort to cannibalism. Respiratory tube on the 8th segment is long, extending to legs and unlike the short tube on Nigronia serricornis. Life cycle two to three years. Larvae pupate at water’s edge, under rocks or moss in spring for about 3 weeks. Pupa can be identified by wing pads – wide white band is N. fasciatus. Narrow white band is N. serricornis. When disturbed C. fasciata curls its body to the side while N. serricornis forms a circle with head touching abdomen tip. Adults live about a week.
One report of Biting Midges (Punkies) Ceratopogon fusicornis feeding on a live adult.

Comments: Northern Ontario – Leeds/Greenville and Barrie. Also Northern Michigan and New Brunswick. Of the two species present in Ontario, N. fasciata more common in northern Ontario and N. serricornis is more common in the south.

For information on synonyms, references and type specimens see next page