Figure 14 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 14 - Comparison of the mesoventral process in Hydrobius. A Large and acute process found in all northern European variants of Hydrobius fuscipes, here represented by a specimen of Hydrobius fuscipes fuscipes B Small and blunt process characteristic of Hydrobius arcticus.