Larval Diagnosis

Larvae of Rhithrogeninae are identified by having the apices of the forefemora with a dorsal process that is projected and is narrower than the ventral process (as in Fig. 81). The mouthparts tend to be adapted for scraping diatoms as seen by the enlarged maxillary palps in most genera (as in Fig. 52), although in some less common genera the mouthparts are adapted for carnivory. Some Rhithrogeninae have a vestigial median caudal filament (as in Fig. 9).

Adult Diagnosis

Adults of Rhithrogeninae are differentiated from those of Ecdyonurinae by having the medial depression of mesothoracic furcasternum convergent anteriorly (as in Fig. 119). The rounded prosternum that lacks a transverse and longitudinal ridge will differentiate adults from those of Heptageniinae (Fig. 121).


Holarctic, Oriental, Neotropical.