Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

Toggle Menu

Athericidae, Atherix (Snipe Flies) of Michigan - Identification

Atherix Meigen is one of two Nearctic genera, and the only one found in Michigan. (The other genus, Suragina Walker, is found in southwestern Texas south, and is known to bite both man and other mammals)(Courtney et al. 1995, Webb 1977). Two species have reported from Michigan. A. variegata Walker, which is commonly found in trout streams in the northern part of the Lower Peninsula, and A. lantha Webb in the southeastern Lower Peninsula. Atherix lanthus larva - Aquatic Insects of Michigan - Ethan Bright copyright 2006The former species is widespread in the north-central part of North America, from South Dakota east to central Indiana, north to the shore of Hudson Bay (Webb 1977).Atherix egg mass over WB Sturgeon - photo Ethan Bright copyright 2005

Larvae are usually burrowers and most commonly found within the substrate of riffles. They are predaceous on other invertebrates, principally chironomids and small mayflies. They are typically are found in cooler streams and rivers throughout the state. Pupation usually occurs in the soil along the stream's edge (Webb 1981). After mating, adult females congregate to oviposit egg masses on overlying vegetation and under bridges over streams and rivers (Figure). Eggs are adhered on to an overlying structure, and the females die thereafter (dead females are frequently found among the egg masses). Larvae hatch from the eggs and fall into the stream where they develop and eventually pupate.

Key to Adults (from Webb 1977)

1a Males 2
1b Females 3
2a(1a) Eyes separated by a distance less than 1/2 the width of the anterior ocellus Atherix lantha Webb
2b Eyes separated by a distance greater than 1/2 the width of the anterior ocellus Atherix variegata Walker
3a(2b) a. Furca distinctly constricted apically Atherix lantha Webb
b. Genital chamber with two lateral rows of short spines anterior to the genital opening, separated medially
3b a. Furca only moderately constricted subapically Atherix variegata Walker
b. Genital opening covered with coarse acute spines


    Courtney GW, Merritt RW, Teskey HJ, Foote BA. 1995. Aquatic Diptera. Part One. Larvae of Aquatic Diptera, pp. 484-548 in Merritt RW, Cummins KW, An Introduction to the Aquatic Insects of North America, Third Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa, USA.
    Webb, DW. 1977. The Nearctic Athericidae (Insecta: Diptera). Journal of the Kansas Entomological Society 50(4):473-495.
    Webb, DW. 1981. Athericidae, pp. 479-482 in McAlpine et al., Manual of Nearctic Diptera. Volume 1. Research Branch Agriculture Canada Monograph 27. Biosystematics Research Institute, Ottawa, Canada.

Page created: April 10, 2006: Last updated: November 8, 2013 (EB)