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| Insects of Britain and Ireland: the genera of Syrphidae (hoverflies) |
Elophilus, Eristaloides, Eristalomya, Eristalomyia, Helophilus Leach, Tubifera
Adult flies. The flies variously bumblebee-like (E. intricarius), or hivebee-like (E. tenax, E. pertinax, E.rupium), or resembling a mining bee, or resembling Colletes, or vespid wasp-like, or cimbicid sawfly-like, or muscid-like; black to dark brownish, variously unmarked or conspicuously marked with tawny or yellow; medium sized to large; 10.5–16 mm long. Wings 6.5–13 mm long.
The head somewhat wider than the thorax to about the same width as the thorax. The face not flat or retreating between antennae and mouth; with a central knob. The eyes not spotted, hairy. Antennae relatively short, drooping; with their bases approximated (seated on a tubercle); black, or ferruginous, or black and ferruginous, or black and tawny. The third antennal segment ovoid or orbicular. The antennal bristle dorsal; about as long as the third segment to much longer than the third segment; basally plumose, or simple.
The humeri hairy, and readily visible behind the head. The thorax pubescent without stiff bristles interspersed; plain; without longitudinal stripes. The scutellum at least partly yellow, or brownish, ferrugineous or tawny, or whitish (often ferrugineous or tawny, not black). Wings patterned to plain (colourless, or tinged brown near the costa, sometimes with a large dark central patch); divergent in repose, or divergent in repose to incumbent and almost parallel in repose. Wing veins R2+3 and R4+5 forming a closed cell. The anterior cross vein R-M in cell R5 crossing it before the middle of the adjoining discal cell to crossing it at or beyond the middle of the adjoining discal cell (before or near the middle). Vein R4+5 with a conspicuous curve projecting into the cell R5; without a backwardly projecting, incomplete transverse veinlet. The lower outer marginal vein more or less parallel with the posterior wing margin. The upper and lower outer marginal cross veins more or less continuous. The upper outer marginal cross-vein gently curved (almost straight); not re-entrant. The alula distinct. The hind femur distally with neither a triangular plate nor a tooth.
The abdomen usually markedly wider than the thorax (anteriorly); obovate. The male abdomen with 4 visible segments. The abdomen conspicuously furry; contrastingly patterned (but then sometimes pale- to ginger-tailed only, e.g., the ginger bumblebee-like E. intricarius), or not contrastingly patterned. The patterning variously attributable to the furry hair coat, or not attributable only to the hair coat. The tergite patterning involving 2 (only, sometimes), or 2 and 3. The colour-patterned tergites marked with tawny. The tergite patterning confined to tergite 2, or not confined to one tergite. The dorsum of tergite 2 exhibiting a wineglass-shaped black area, or without a wineglass-shaped black area. The tergite bands widely medianly interrupted (the components sometimes complexly shaped). The spiracles of the third abdominal segment borne at or near the anterior corner of each side.
Larvae and pupae. The larvae tapering posteriorly; tailed. The anal segment abruptly constricted basally into the long, narrow tail; at least as long as the rest of the body (rat-tailed maggots). The larvae scarcely flattened; pallid, plain; without thoracic hooks; mouth without triangular sclerites; anal segments with lappets. The larvae more or less aquatic to semi-aquatic; saprophagous, or saprophagous and coprophagous (in decaying vegetation in organically rich ponds and ditches, also farmyard manure and silage).
Classification. Subfamily Milesiinae; tribe Eristalini.
British representation. 10 species in Britain.
Illustrations. • Eristalis cryptarum (Beautiful Hover-Fly: B. Ent. 432). • Eristalis cryptarum: B. Ent. 432, legend+text. • Eristalis cryptarum: B. Ent. 432, text cont.. • E. arbustorum, E. horticola, E. rupium, E. tenax: Verrall. • E. tenax, female, with Brachypalpoides, Criorhina and Xylota. SYRPHIDAE. 1, Criorhina ranunculi, male; 2, Eristalis tenax, female; 3, Brachypalpoides lentus, male; 4, Xylota sylvarum, female. Adapted from C.O. Hammond (Colyer and Hammond, 1968), with names updated. • 15 genera (from Walker). 1, Ceriana conopsoides (adventive?), head in side view and extremity of wing. 2, Callicera aurata, with detail of antenna. 3, Microdon mutabilis, antenna and wing. 4, Eumerus strigatus, head in side view and wing. 5, Eristalis tenax: male head from above (5a), female head from the side (5b), and wing of female (5c). 6, Helophilus pendulus: head of male from above (6a) and from the side (6b), and extremity of wing (6c). 7, Merodon clavipes (extinct in Britain): head in side view, and hind leg of male. 8, Tropidia scita, male: head and extremity of wing. 9, Syritta pipiens, male, with head in side view (9a). 10, Xylota sylvarum, male: head (10a), antenna (10b), and base of hind leg showing coxa with a small spine (10d). 11, "Milesia speciosa" (Caliprobola speciosa?): head in side view (11a), wing extremity (11b), and base of hind leg (11c). 12, Criorhina berberina, with side view of head. 13, Volucella bombylans: side view of head (13a), antenna (13b), and wing extremity (13c). 14, Sericomyia silentis, with head from side (14a) and claw joint of tarsus (14b). 15, Orthoneura nobilis. From Walker (1851, Plate IX), with approximate lengths (head to abdominal tip) indicated. • Eristalis fumipennis, Leucozona lucorum, Parhelophilus frutetorum, Spilomyia femorata: Stephens 1846. SYRPHIDAE. 1, Leucozona lucorum (as Syrphus lucorum). 2, Parhelophilus frutetorum (as Helophilus frutetorum). 3, Eristalis fumipennis Stephens (alien - a neotropical species). 4, Spilomyia femorata. From Stephens, 1846. • E. arbustorum, with assorted other Syrphidae (adult forms). Syrphidae. 1, Baccha elongata, female; 2, Neoascia podagrica, male; 3 and 4, Melanostoma scalare, male and female respectively; 5, Syritta pipiens, male; 6, Tropidia scita, male; 7 and 8, Sphaerophoria scripta, male and female respectively; 9, Sericomyia silentis, male; 10, Xylota segnis, male; 11, Rhingia camprestris, female; 12, Eupeodes luniger, male; 13, Episyrphus balteatus, female; 14, Helophilus transfugus L., female (= ?); 15, Chrysotoxum cautum, male; 16, Eristalis arbustorum, male. Adapted from C.O. Hammond (Colyer and Hammond, 1968).
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 genera of Syrphidae (hoverflies). Version: 27th July 2019. delta-intkey.com’.
