Volume 167 of Zoologica documents the current knowledge on immature stages of the water beetle family Haliplidae. The family has a worldwide distribution with 233 species according to very recent studies. The Haliplidae have a complete metamorphosis consisting of egg, 1st instar larva, 2nd instar larva, 3rd instar larva, pupa and adult. From about 25% of all species one of the immature stages is known. The lack of knowledge is greatest in the Oriental, Neotropical and Afrotropical Regions. In this study all available knowledge is referenced and many illustrations and photos of the described species are included. A historical review is given for all works on Haliplidae dealing with the immature stages in general and identification keys.
More details are given for each species. The author added new and additional figures and descriptions of Brychius elevatus (2nd instar larva), Haliplus (Apteraliplus) parvulus (3rd instar larva), Haliplus (Haliplidius) confinis (1st, 2nd and 3rd instar larva), Haliplus (Haliplidius) obliquus (2nd instar larva), Haliplus (Haliplidius) varius (2nd instar larva), Haliplus (Haliplus) fluviatilis (2nd and 3rd instar larva), Haliplus (Haliplus) fulvicollis (3rd instar larva), Haliplus (Haliplus) furcatus (3rd instar larva), Haliplus (Haliplus) heydeni (1st, 2nd and 3rd instar larva), Haliplus (Haliplus) immaculatus (1st, 2nd and 3rd instar larva), Haliplus (Haliplus) lineolatus (1st, 2nd and 3rd instar larva), Haliplus (Haliplus) ruficollis (1st, 2nd and 3rd instar larva), Haliplus (Haliplus) sibiricus (1st, 2nd and 3rd instar larva), Haliplus (Liaphlus) flavicollis (2nd and 3rd instar larva). Suggestions are made for further research to throw a better light on the phylogeny of the Haliplidae.

This study is of interest to biologists working in the field of hydrobiology, water quality management and researchers interested in the life cycle of insects, specifically Haliplidae, also known as Crawling Water beetles.