Leucozona americana Curran, 1923:38

The subgenus Leucozona s. str. differs by having abdomen oval, marginated; 2nd tergum mainly white, grey or pale yellow, with a medial lack vitta; 3rd and 4th terga black (sometimes anterior margin of 3rd tergum whitis); and wing with a medial dark macula. The subgenus Ischyrosyrphus has abdomen parallel-sided, mostly unmarginated (sometimes with very weak margin on terga 4th and 5th); tergum 2 black with pair of large subbasal subquadrate pale maculae, medially joined or not; 3rd and 4th terga with small pale maculae; wing without dark macula, except dark stigma.

Leucozona (Leucozona) americana Curran, 1923.

Curran, C.H. (1923) Our North American Leucozona, a variety of lucorum (Syrphidae, Diptera). The Canadian Entomologist 55, 38. [1923.03.23]

Leucozona americana differs from L. lucorum by having basoflagellomere a little shorter; facial tubercle longer, less prominent; pile of the scutum and scutellun wholly pale yellow; abdomen wholly black pilose beyond the second tergum; 1st and 2nd terga yellow, yellow pilose; 3rd tergum black, yellow pilose on anterior 2/3, black pilose on posterior 1/3; 4th-9th terga black pilose. L. lucorum has scutum yellow pilose, but rather tawny on the lateral margins and scutellum; terga are yellow pilose, except 3rd tergum dorsally and laterally black pilose on black areas, and sometimes, in the male, a few black pile on 4th tergum. The result is that the shining apical terga appear metallic black in L. lucorum, while in L. americana they are deep solid black.

Body length: 9.8-13.0 mm (Curran 1923).

Nearctic species known from Alaska, Yukon to Labrador, south to Oregon, Colorado, and New York.

Adults of L. americana assemble on hill tops, presumably for mating (D.M. Wood, personal communication in Vockeroth 1992, as Leucozona lucorum).

Larva (from Dixon 1960, as Leucozona lucorum).

Average length 10-15 mm., width 3.5 mm., height 2 mm. ; brown with yellow-orange chevrons; dorsoventrally flattened, tapering anteriorly, cuspidate posteriorly, scalloped in outline; transverse wrinkles present; fleshy projections and prominences absent; ventral sole present; integumental vestiture absent; body papillose; segmental ornamentation of single spines each mounted on a papilla, twelve spines on segments 4-11, eight on segment 12; external mouth hooks present; aphidophagous.
Posterior respiratory process: postero-dorsal ; one and a half times as long as broad at the base, basal two-thirds parallel-sided, nodular; apical one-third rounded, smooth, a constriction separating basal and apical parts; entirely sclerotized; spiracular plates separated by a pronounced median groove; hind margin of circular plates just posterior to inner end of spiracles II, circular plates towards median groove; apices of well-developed triangular dorsal spurs between inner ends of spiracles II; interspiracular ornamentation of large prominences, an inner opening between spiracles I and II; three pairs of straight spiracles mounted on slight carinae curving over edge of spiracular plates when viewed from above, spiracles radiating on each spiracular plate.