#3
It is a Tanytarsini and most likely the genus Rheotanytarsus. The antennal pedestals do not have a median extension, so Stempellina/Zavrelia/Stempelinella can be excluded. The lauterborn organs are large and are placed on relatively short pedestals, so Micropsectra/Tanytarsus can be exluded. Then it becomes difficult looking at the photographs. The third antennal segment seems shorter than the second segment and the pedestal of the lauterborn organ seems larger than the third segment. If this is true than it must be Rheotanytarsus. If otherwise than Cladotanytarsus/Paratanytarsus may be in the picture. Cladotanytarsus has a row of teeth at the innerside of the anal claws and Paratanytarsus has characteristic epipharynx teeth (3-5 distinct teeth).