Hydrachna processifera Koenike, 1903
Type material: Paratypes deposited in SMF, catalogue numbers 43764-0506-VIE/111, 43765-0519-VIE/111, 43784-0520-VIE/112 (GBIF 2022) .
Type locality: Germany: Bremen, close to peat channel (GBIF 2022; Koenike 1903).
Geographical distribution: Palaearctic (Davids et al. 2006).
Distribution in Portugal: South: Alentejo (Valdecasas 1988), 10 km north of Alcácer do Sal (Lundblad 1956).
Ecological notes: Freshwater, with some saltwater influence, in slow-moving streams and standing waters, present in some plants including grasses (Lundblad 1956); Larval insects hosts: Dytiscidae, coleopterans (Davids et al. 2006).
Hydrachna rubicunda Viets, 1930
Type material: Holotype deposited in SMF, catalogue number 43790-3819-VIE/112 (GBIF 2022).
Type locality: Spain (GBIF 2022): Zaragoza, Balsa de la Torre Choa (Viets 1930).
Geographical distribution: Iberian Peninsula (Lundblad 1956; Valdecasas 1988).
Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Lundblad 1956).
Ecological notes: Freshwater, at standing and temporary waters, including rice field channels; present in aquatic plants, such as Batrachium spp., Myriophyllum spp., Nymphea spp. (Lundblad 1956) .
Remarks: Possible synonym to Hydrachna globosa (Davids et al. 2006) .