Key: Step 724. Orthocladiinae 136 Tvetenia/Dratnalia

724a. Exuvial length less than 4mm. Apical filament of thoracic horn about 6 times the length of the swollen section at base (050h.jpg). Tergite I without a posterior transverse row of teeth.

Tvetenia duodenaria

724b. Exuvial length over 6mm. Apical filament of thoracic horn less than twice the length of the swollen base (050f.jpg). Tergite I with a posterior transverse row of teeth.

Dratnalia potamophylaxi
Decision path