Synonyms and other taxonomic changes
Polybiomyia bellardii Shannon 1925
Hull 1930 (per Systema Dipterorum
Thorax: Pleura (= lateral faces of the thorax) with no yellow markings...mostly black but often tinged reddish in some areas. Dorsum of thorax black except for symmetrically-paired yellow spots on humeri (= anterior corners) and notopleura (= areas at lateral edges of suture, just forward from & above the wing bases). Scutellum yellow with narrow transverse black stripe just anterior to rounded hind edge.
Legs: Mostly red (but bases of tibiae yellowish).
Abdomen: 1st segment much-tapered rearward, mostly black with some red. 2nd segment quite narrow & elongate...gradually widening in posterior 1/3 of its length, two small lateral yellow spots anteriorly but otherwise mostly red with lesser areas of black and a conspicuous posterior yellow band. 3rd segment significantly widened posteriorly, black with a posterior yellow band...and usually with a pair of fainter pollinose (="dust"-like), straight to slightly-curved tranverse markings on either side of the middle of posterior portion of the dorsum (anterior to yellow posterior band). 4th segment tapering in diameter but similar to 3rd in color & markings.
For Shannon's 1925 key to Polybiomyia
(and disregard the green highlighted text, which pertains to the species in that post).
Hull F.M. (1930) Some notes and descriptions of Cerioidine wasp-waisted flies (Syrphidae: Diptera). Psyche 37:178-181. (Full Text
Shannon, R.C. (1925) The syrphid–flies of the subfamily Ceriodinae in the U.S. National Museum Collection. Insecutor Inscitiae Menstruus, No. 13, 48–65. (Full Text