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| Insects of Britain and Ireland: the families of Hemiptera |
Water-scorpion and Water Stick-insect.
Salient features of adults. Foraging under water.
Predacious (on arthropods, tadpoles and small fish). Large; 18–22 mm long (Nepa cineria), or 30–35 mm long (Ranatra linearis); fliers; swimming and moving under water the right way up; relatively stout bodied (Nepa cineria), or with narrow-elongate bodies (Ranatra linearis); conspicuously stilt-legged (Ranatra linearis), or not stilt-legged (Nepa cineria). Rostrum clearly separated ventrally from the prosternum by a sclerotized gula. Antennae inserted underneath the head and much shorter than it, generally invisible from above; non-aristate. Ocelli absent. Fore-wings well developed; in the resting insect lying more or less flat over the abdomen; differentiated into a basally thickened and a distally membranous region; with a clavus. Fore-legs modified and raptorial. The abdomen terminating in a long, bristle-like respiratory siphon (this comprising two filaments, which may become detached as in the illustration).
With conspicuously modified, raptorial forelegs, and the abdomen terminating in an elongated respiratory siphon.
Taxonomy. Suborder Heteroptera; Notonectoidea.
British representation. 2 species in Britain; genera 2. Nepa, Ranatra. E.g., Ranatra linearis (Linear Water-scorpion).
Illustrations. • Ranatra linearis (Linear Water-scorpion: B. Ent. 281). • Ranatra linearis (dissections: B. Ent. 281). • Ranatra linearis (legend+text: B. Ent. 281). • Ranatra linearis (text: B. Ent. 281, cont.). • Nepa cinerea (Water Scorpion: B. Ent. 700). • Nepa cinerea (Water Scorpion: B. Ent. 700, legend+text). • Nepa cinerea (Water Scorpion: B. Ent. 700, text cont.). • Ranatra linearis (Shaw and Nodder, about 1802). • 'The Great Surinam Nepa' (Exotic species, Shaw and Nodder, about 1798). • Nepa, Ranatra and other aquatic bugs (Southwood & Leston). • Ranatra linearis, with Corixidae, Notonecta and Plea: Saunders (1892).. NEPIDAE. 1, Ranatra linearis. NOTONECTIDAE. 2, Notonecta glauca. PLEIDAE. 3, Plea atomaria (as P. minutissima). CORIXIDAE. 4, Corixa punctata (as C. geoffroyi). 5–8, Sigara spp., under Corixa in the original legend. 5, Sigara concinna; 6, Sigara dorsalis (as C. striata); 7, Sigara falleni; 8, Sigara cavifrons. 9, Cymatia coleoptrata (as Corixa). 10, Micronecta scholtzi (as Sigara). From Saunders (1892). • Nepa cinerea, with Miridae, Aphelocheirus and Ilyocoris: Saunders, 1892.. MIRIDAE. 1, Psallus rotermundi Schultz., = ? 2, Plagiognathus albipennis; 3, Plagiognathus arbustorum. 4, Salicarius roseri. 5, Monosynamma bohemanni. 6, Plagiognathus saltitans. 7, Asciodema fieberi. NAUCOCORIDAE. 8, Ilyocoris cimicoides. APHELOCHEIRIDAE. 9, Aphelocheirus aestivalis f. montandoni. NEPIDAE. 10, Nepa cinerea. From Saunders (1892).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Hemiptera. Version: 27th July 2019. delta-intkey.com’.
