1.a. Females 6-10 mm, males 4.5–7 mm. Prosoma yellow-brown, often with fine black pattern. Opisthosoma grey with bright pattern. Anterior spinnerets clearly longest, tracheal stigma in normal position (i.e. in front of spinnerets). Legs III and IV not remarkably hairy. In the highlands and Alps ... Cybaeus

1.b. 10–12 mm, dark-brown to black. All spinnerets of approx. same length. Tracheal stigma anteriorly positioned, just behind epigastric furrow. Legs III and IV with long hairs. Living in water, rarely found ... Argyroneta

Photos: Argyroneta aquatica