First description of the female subimago of Behningia baei McCafferty & Jacobus, 2006 (Ephemeroptera, Behningiidae), with notes on nymphal sand-burrowing behaviour.

BACKGROUND: Behningia baei McCafferty & Jacobus, 2006 was only known from the nymphal stage and recorded from two localities in Thailand. While the winged stages have been described for four congeners of Behningia, those of B. baei have not yet been documented. NEW INFORMATION: Here, we present the first morphological description of the female subimago of B. baei based on reared specimens collected from sandy-bottomed rivers in northern Thailand. We compare diagnostic characters of the female subimago with those of known species of Behningia. In addition, we provide data on burrowing behaviour in fine-sand substrate. Our findings bring new biological and behavioural data for this rare genus.