Eupeodes species are robust with shining or subshining thorax; abdomen oval, usually flattened, strongly margined; terga usually with pale yellow to reddish yellow maculae commonly lunulate or with fasciae of similar color almost straight, wavy, or distinctly emarginate; rarely with about apical one-third of abdomen reddish above or with tergites mostly or entirely black. Usually, the vein R4+5 is nearly straight, the metasternum pilose and male terminalia can be either small, scarcely apparent from above or greatly enlarged, protruding as bluntly rounded cylinder at apex of abdomen, like in E. volucris.
Adapted from Vockeroth (1992).
MALE.
Head: Frons pale yellow. Face pale yellow with distinct dark brown to black medial vitta on lower three-fIfths; vitta continuing on each side on anterior half of lower facial margin; gena pale brown to black posteriorly. Antenna entirely black. Occiput moderately broad dorsally .
Thorax: Scutum, pleura, and scutellum with white to pale yellow pile. Metasternum pilose. Wing extensively bare; cells c and bm with scattered microtrichia only at extreme apex; all cells bare at base; only about apical one-quarter and posterior one-third of wing with moderately dense microtrichia. Vein R4+5 nearly straight. Legs: Basal one-third to three-fifths of pro- and mesofemora and about basal four-fIfths of metafemur black; legs otherwise dark yellow; pili of posterior surface of pro- and mesofemora yellow.
Abdomen: Terga 2-4 each with pair of large pale yellow maculae well-separated from lateral margins; maculae of terga 3 and 4 slightly oblique and with anterior margin slightly concave; tergum 4 with posterior margin mostly narrowly pale yellow; tergum 5 black with posterior margin narrowly yellow and usually with part or all lateral margin narrowly yellow to reddish. Sterna 1-3 pale yellow, each with black fascia; sternum 4 yellow-orange. Genitalia very large, protruding at apex of abdomen as large shining black cylinder; upper surface composed of nearly fused sterna 7 and 8; surstyli on under side of cylinder, each very long, slender, distinctly curved and with enlarged and notched apex.
FEMALE.
Frons with upper two-thirds black and with large undivided semicircular black macula above antennae, with well-defined narrow pale yellow fascia between two black areas; lower part of upper black area with pair of large lateral whitish pollinose maculae. Femora usually less extensively black basally than in male; metafemur black on basal two-fifths to three-quarters. Sternita 4 and 5 yellow-orange.
E. volucris is similar to E. perplexus but differs by having the scutellum with only pale pili; frontal triangle of male entirely yellow; frons of female with single semicircular brown to black maculae above antennae; this macula separated from black dorsal part of frons by well-defined pale yellow band. The male terminalia is very large (small in E. perplexus), projecting at apex of abdomen as long bluntly rounded cylinder. Female of E. volucris have sterna 4 and 5 yellow-orange, while females of E. perplexus have a black fascia on sterna 4 and 5.
The species of Eupeodes show an unusual amount of intraspecific variation in color of head, legs, abdomen, and body hairs; in some and perhaps in all species, these variations seem to result from differences in temperature during the pupal stage (Dusek and Laska 1974). Structural differences between the species are few; in some, as in E. volucris and E. americanus, the male genitalia are very distinctive, but in most cases the differences are slight and there is apparently moderate variation within some species. As a result, some specimens are very difficult identify properly. They may represent unusual variations of known species or, in a few cases, undescribed species. It seems unwise, in a genus as difficult as this one, to treat as distinct species forms known from only one or a few specimens (Vockeroth 1992).
Body lenght: 6.3-9.8 mm.
In Rotheray and Gilbert (1989), Eupeodes was placed as sister group of Scaeva. In 1999, results by Rotheray and Gilbert using larval morphological characters resolved Eupeodes as siter group of Scaeva and Ischiodon.
Mengual et al. (2008) studied the subgenera Eupeodes (Macrosyrphus) and Eupeodes (Metasyrphus) and results supported Macrosyrphus as sister group of Metasyrphus. The previously considered subgenus Lapposyrphus was placed as a separate genus, resolved in the same clade as Eupeodes, but closer to Pseudodoros + Simosyrphus + Scaeva.
Heiss (1938) listed 20 species of aphids as larval hosts; an additional host record, Cinara ponderosae, was mentioned by Vockeroth (1992). A complete list of aphid preys (Aphididae) was given by Rojo et al. (2003), including larva of Pieris brassicae (Lepidoptera) (original reference: Daminova 1989).
E. volucris is multivoltine. Jones (1922) gave 21 days as the average period from egg to adult in the laboratory.
Species known from British Columbia to Ontario, south to Mexico (Chiapas). It was introduced in Hawaii but it is not established.
Egg (from Chandler 1968):
White, greying slightly on development; mean length 957 µ (n = 230, range 820-1110 µ), mean width 427 µ; strongly tapering towards one end; marked surface projections dorsally and laterally. Chorionic sculpturing: dorsally, projections mushroom-shaped, neck wider than long, appearance of units dendritic, ramification with extensive contact between branches of neighbouring units; ventrally, sculpturing of large dots and rods not aggregated into discrete groups. Ecological notes: Common; eggs found from May to October; wide host acceptance range; eggs laid singly.