British Insects: the Families of Diptera

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L. Watson and M. J. Dallwitz

Syrphidae

Hover-flies, Drone-flies.

Adult insects. Small to large. The face in lateral view deeply excavated between the antennae and the edge of the mouth, or not deeply excavated between the antennae and the edge of the mouth. Antennae 3 segmented; ‘modified’; with a non-annulated terminal segment; aristate; the arista apical (Callicera), or dorsal (sometimes plumose). Ptilinal suture clearly defined (sometimes, ostensibly), or absent or weakly defined. Ocelli present; 3. Ocellar bristles mostly absent. Eyes asymmetric, nearly or quite connected above the antennae (in most males), or rounded, well separated. Lower orbital bristles mostly absent. Post-vertical orbital bristles mostly absent. Mouthparts non-piercing. The maxillary palps 1 segmented; porrect. Wings with a discal cell (large); with a subapical cell; with a closed anal cell. The anal cell relatively long. Sub-costa apparent; reaching the costa independently of vein 1 (mostly?), or distally forked, to join both the costa and vein 1. The leading edge veins not noticeably stronger than the rest. Wings exhibiting a ‘vena spuria’ (this nearly always readily detectable, and also with a secondary margin formed by veins, more or less parallel with the hind margin itself, the latter being often hardly visible). Wing vein 3 not forked. Wing vein 6 present; reaching the wing margin. Wings with the lower calypter much reduced or absent; patterned, or unpatterned. Feet without a triple pad. Neither parasitic nor predatory (imbibers of nectar and plant exudates, including important pollinators).

Larvae and pupae. The larvae living in very liquid media, or aquatic (including ‘rat-tailed maggots’, equipped with a narrow, much extended rear breathing tube for accessing air), or terrestrial; phytophagous, or saprophagous to coprophagous (many eaters of ‘filth’, and some consuming excrement and decaying material in the nests of bees, wasps and hornets), or predatory (including voracious aphid-eaters, slug-like in appearance); acephalic. The pupae enclosed within a puparium.

Comments. Small to large, often brightly coloured, mostly bristle-less, spectacularly hovering flies. Adults mostly feeding on nectar, including numerous wasp and bee mimics. The mature larvae are distinguishable from those of all other Diptera, in having the posterior pair of breathing tubes fused into a single, elongate (brown or black) structure..

Classification. Suborder Brachycera; Division Muscomorpha Aschiza; Superfamily Syrphoidea.

British representation. 265 species in Britain. Genera about 70; Anasimyia, Arctophila, Baccha, Blera, Brachyopa, Brachypalpoides, Brachypalpus, Caliprobola, Callicera, Chalcosyrphus, Chamaesyrphus, Cheilosia (about 35 species), Chrysogaster, Chrysotoxum, Criorhina, Dasysyrphus, Didea, Doros, Eristalis, Eriozona, Eristalinus, Epistrophe, Episyrphus, Eumerus, Eupeodes, Ferdinandea, Hammerschmidtia, Helophilus, Heringia, Lejogaster, Lejops, Leucozona, Mallota, Melangyna, Melanogaster, Melanostoma, Meligramma, Meliscaeva, Merodon, Microdon, Myathropa, Myolepta, Neoascia, Orthonevra, Paragus, Parasyrphus, Parhelophilus, Pelecocera, Pipiza, Pipizella, Platycheirus, Pocota, Portevinia, Psilota, Rhingia, Riponnensia, Scaeva, Sericomyia, Sphaerophoria, Sphegina, Syritta, Syrphus, Trichopsomyia, Triglyphus, Tropidia, Volucella, Xanthandrus, Xanthogramma, Xylota.

Illustrations. • 15 genera (from Walker). • 18 genera (from Walker). • Lejops vittatus (Yarmouth Hover-fly: B. Ent. 429). • Lejops vittatus (detail: B. Ent. 429). • Lejops vittatus (dissections: B. Ent. 429). • Lejops vittatus: B. Ent. 429, legend+text. • Lejops vittatus: B. Ent. 429, text cont.. • Ceriana conopsoides (Long-horned Hover-Fly. Not British: B. Ent. 186). • Ceriana conopsoides: B. Ent. 186, legend+text. • Ceriana conopsoides: B. Ent. 186, text cont.. • Chalcosyrphus nemorum (Four-spotted Hover-fly: B. Ent. 425). • Chalcosyrphus nemorum: B. Ent. 425, legend+text. • Chalcosyrphus nemorum: B. Ent. 425, text cont.. • Eristalis cryptarum (Beautiful Hover-Fly: B. Ent. 432). • Eristalis cryptarum: B. Ent. 432, legend+text. • Eristalis cryptarum: B. Ent. 432, text cont.. • Merodon clavipes (Beautiful Merodon Hover-fly. Extinct British species: B. Ent. 098). • Merodon clavipes: B. Ent. 098, legend+text. • Merodon clavipes: B. Ent. 098, text cont.. • Microdon mutabilis (Bee-like Hover-fly: B. Ent. 070). • Microdon mutabilis: B. Ent. 070, legend+text. • Microdon mutabilis: B. Ent. 070, text cont.80. • Caliprobola speciosa (Beautiful Milesia Hover-fly: B. Ent. 034). • Caliprobola speciosa: B. Ent. 034, legend+text. • Caliprobola speciosa: B. Ent. 034, text cont.. • Rhingia campestris (Chequered-bodied Hover-fly: B. Ent. 182). • Rhingia campestris: B. Ent. 182, legend+text. • Rhingia campestris: B. Ent. 182, text cont.. • Scaeva pyrastri (Concolourous Hover-fly: B. Ent. 509). • Scaeva pyrastri: B. Ent. 509, legend+text. • Scaeva pyrastri: B. Ent. 509, text cont.. • Tropidia scita (British Tropidia Hover-fly: B. Ent. 401). • Tropidia scita: B. Ent. 401, legend+text. • Tropidia scita: B. Ent. 401, text cont.. • Volucella inflata (Inflated Hover-fly: B. Ent. 452). • Volucella inflata: B. Ent. 452, legend+text. • Volucella inflata: B. Ent. 452, text cont.. • Paragus haemorrhous: B. Ent. 593. • Paragus haemorrhous: B. Ent. 593, legend+text. • Paragus haemorrhous: B. Ent. 593, text, cont.. • Chrysotoxum octomaculatum Curtis: B. Ent. 653. • Chrysotoxum octomaculatum Curtis: B. Ent. 653, legend+text. • Chrysotoxum octomaculatum Curtis: B. Ent. 653, text cont.. • Trichopsomyia flavitarsis: B. Ent. 669. • Trichopsomyia flavitarsis: B. Ent. 669, legend+text. • Trichopsomyia flavitarsis: B. Ent. 669, text cont.. • Baccha elongata: B. Ent. 737. • Baccha elongata: B. Ent. 737, legend+text. • Baccha elongata: B. Ent. 737, text cont.. • Eumerus sabulonum: B. Ent. 749. • Eumerus sabulonum: B. Ent. 749, legend+text. • Eumerus sabulonum: B. Ent. 749, text cont.. • Leucozona lucorum: B. Ent. 753. • Leucozona lucorum: B. Ent. 753, legend+text. • Leucozona lucorum: B. Ent. 753, text cont.. • Eristalis fumipennis, Leucozona lucorum, Parahelophilus frutetorum, Spilomyia femorata: Stephens 1846.


To view the illustrations with detailed captions, go to the interactive key. This also offers 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.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Diptera. Version: 1st January 2012. http://delta-intkey.com’.

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