Originally described as Baccha gracilis by Williston, Hull (1949) included this taxon in his new genus, Leucopodella.
Synonyms:
Baccha gracilis Williston, 1891: 34.
Baccha gowdeyi Curran, 1926: 102.
Baccha asthenia Hull, 1948: 4.
Baccha carmelita Hull, 1948: 9.
Baccha estrelita Hull, 1948: 1.
From original description (Williston 1891).
Head: Face and frontal triangle of the male shining bronze-green, thickly covered (except along the middle of the trianglo) with nearly white dust; in the female the colour is shining blue, conocaled beneath nearly white dust, except a streak along the front and at the vertex. Face gently convex transversely, in profile nearly straight and gently receding from the antennae to the oral margin.
Thorax: Mesonotum shining bronze in the male, blue in the female. Scutellum blue. Legs light yellow; a preapical blackish ring on the hind femora, and a brown or brownish ring on the hind tibiae; hind metatarsi elongate, somewhat thickened and infuscated, the terminal joints also somewhat brownish. Wings nearly hyaline, the stigma lightly brownish.
Abdomen: first segment coloured like the scutellum; second segment subopaque black, very slender, and of nearly uniform width; third segment brown or black, with the baso yellow, its width behind in the male scarcely a third of the length (in the female the third segment may have a.yellow median stripe); fourth segment similar in colour to the third, usually with a more or less complete median yellow stripe: fifth segment of the female yellowish on the anterior angles; hypopygium small, shining black.
New description:
MALE.
Head: Face straight without facial tubercle, black densely grey pollinose, yellow pilose; gena narrow, black; frontal triangle black, densely grey pollinose with a medial shiny vitta, yellow pilose; vertical triangle black, black pilose; holoptic, eye bare; antenna orangish-brown, basoflagellomere darker dorsally; occiput narrow, black, silver pollinose, yellow pilose.
Thorax: Scutum shiny black, punctuate, golden yellow pilose; postpronotum yellow, bare; scutellum black, golden yellow pilose with two long brown bristle-like setae, subscutellar fringe sparse. Pleuron black, withish-yellow pilose; metaepisternum narrowly separated behind metacoxae; anterior anepisternum and metaepisternum bare; metasternum pilose; calypter yellow; plumula yellow; halter brownish-yellow; spiracular fringes yellow. Wing: Wing membrane slightly brown; vein M1 sinuous and angulate; microtrichose except 2nd costal cell bare on basal 1/4, cells R1, CuP and anal lobe bare very basally, and cell BM bare on basal 1/2. Alula narrow, as broad as 2nd costal cell, bare. Legs: Entirely yellow except two apical mesotarsomeres brown, metafemur brown to black on apical 2/3 or less, metatibia dark on apical 2/3 and metatarsus dark.
Abdomen: petiolate, petiole much narrower than thorax. Dorsum mainly black, black pilose with long golden yellow pile on 1st and 2nd terga; 1st and 2nd terga black; 2nd tergum very narrow, tubular; 3rd tergum black with yellow fascia on anterior margin (about 1/6 of tergum length), sometimes with posteromedial yellow vitta on posterior half; 4th tergum black with yellow fascia on anterior margin (about 1/4 of tergum length) joined with medial yellow vitta forming a T-shaped yellow macula, sometimes the yellow vitta reduced to a simple imargination on posterior margin of yellow fascia; 5th tergum black; 1st and 2nd sterna yellow, 3rd sternum yellow on anterior 1/2, otherwise brown.
FEMALE.
Similar to male but differs as follow: fons black densely grey pollinose with a medial shiny black vitta reaching ocellar triangle; 5th tergum black with narrow yellow fascia on anterior margin.
Leucopodella gracilis (Williston, 1891).
Williston, S.W. (1891-92) Fam. Syrphidae. Biologia-Centrali-Americana. Insecta: Diptera 3: 1-56; 57-72; 73-78, pl. 1, 2, figs. 1-12.
unless otherwise stated