British Insects: the Genera of Ephemeroptera
Imago. The compound eyes contiguous (in males), or widely separated (in females); rounded.
Wings unspotted. Fore-wings with R5 and R4 joined basally. Hind-wings present. The hind-wings of the female imagines more than one fifth the length of the fore-wings. Hind tarsi with 5 moveable segments. The hind tarsal claws unalike, being one pointed and one blunt.
The abdomen with two tails. Male claspers crossed. The lobes of the penis narrow, rod-shaped, and widely separated; without recurved appendages.
Nymph. Gills mostly at the sides of the abdomen; not fringed with filaments on both sides; mostly consisting of a plate bearing a tuft of filaments.
Classification. Superfamily Heptagenioidea. Family Heptageniidae.
British representation. 2 species; R. germanica (March Brown Dun, March Brown or Great Red Spinner), and R. semicolorata (Olive Upright Dun, Yellow Upright Spinners).
Illustrations. • Caenis macroura, Cloeon dipterum, Rhithrogena semicolorata: Stephens VI, 1835.
To view illustrations with legends giving names in current use, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa, as well as source references and other relevant material.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the genera of Ephemeroptera. Version: 29th December 2011. http://delta-intkey.com’.