This common and widespread genus includes at least 21 North American species. The larvae live in both rapid and quiet stretches of streams and among rooted plants at the edges of ponds and lakes. They have streamlined bodies that enable them to swim rapidly through the water; when resting, they cling or climb on rocks and other stable substrates. Mainly, they feed as collectors-gatherers of diatoms and tiny bits of organic detritus, occasionally scraping these materials from rock surfaces.
Southeast: 1.8 - 8.1
Upper Midwest: 5.5 and higher
Midwest: 2.8 and higher
Mid-Atlantic: 6 and higher
Collector / Gatherer
Scraper / Grazer
Scraper / Grazer
Widespread (east of the Rocky Mtns.)
+ Expanded Character List
Order: Wings developing in wing pads. Mouthparts suitable for chewing. Gills present on tops and sides of abdomen. Segmented legs present. One tarsal claw per leg. Usually with 3 tails (sometimes 2).
Family: Labrum usually with median notch and antennae usually long (at least two or three times the width of the head). If median notch absent, then antennae long; if antennae shorter, then distal margin of the labrum always notched. Claws of all legs similarly shaped, usually pointed, rarely broad at the apex; claws of varying lengths, if claws of middle and hind legs long and slender, they are usually shorter than tibiae, except for few rare genera. Abdominal gills roughly oval or heart-shaped. Gill lamellae either single, double, or triple folded; rarely with fringe on inner margins, never with terminal filaments or pointed ends. Mature larvae 3-12 mm long.
Genus: From among those of many genera of Baetidae, larvae distinguished by presence of well-developed medial corner of maxillary palp segment 2, villopore present on ventral base of some or all femora, tarsal claws each less than half as long as its tarsus and with single row of denticles, absence or presence of tiny hind wing pads, gills on abdominal segment 1-7 and simple (not folded on themselves), median caudal filament (middle tail) longer than abdominal segment 10 but shorter than cerci (lateral tails).