Figure 16 from: Fossen EI, Ekrem T, Nilsson AN, Bergsten J (2016) Species delimitation in northern European water scavenger beetles of the genus Hydrobius (Coleoptera, Hydrophilidae). ZooKeys 564: 71-120. https://doi.org/10.3897/zookeys.564.6558

Figure 16 - Morphometric differences between morphotypes and effect of body size on Elytral Index (EI) of Hydrobius. EI = length of the elytra / maximum width of elytra. 113 specimens measured. Independently fitted lines for each morphotype are shown, slopes not significantly different. Type specimens and specimens of Hydrobius fuscipes subrotundus and Hydrobius fuscipes fuscipes collected in sympatry (Rinn = locality Rinnleiret (Norway), Mot = Motzen (Germany) and Ola = Öland (Sweden)) are labeled.