THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Small minnow mayflies are ubiquitous and abundant. They can be found in almost any freshwater habitat, usually in a variety of instars.

Baetid larvae have long streamlined bodies with platelike gills on most abdominal segments. They are distinguished from other mayflies by their long antennae, which are usually more than twice as long as the width of their heads. They also have a notch at the end of their labrum, which can be seen when viewed from the front. All of their claws are similar in shape and size. Some may have only two cerci, or the middle cercus may be reduced in length compared to the others.