Asiodidea is a monotypic genus of the tribe Syrphini. A. nikkoensis has postpronotum bare, antenna short, anterior anepisternum bare, abdomen slightly oval, metaespisternum nd metasternum bare, scutum with a well-defined lateral yellow vitta, abdomen strongly margined, and vein R4+5 strongly sinuate.
Asiodidea nikkoensis (Matsumura, 1916).
Matsumura, S. (1916) [Thousand insects of Japan. Additamenta]. Vol. 2 (Diptera). Keisei-sha, Tokyo. p. [2] + 185-474 + [4], pls. 16-25. [1916.07.08] [In Japanese]
New description:
MALE.
Head. Face broad, produced forward, oral tip anterior to antennal base, with distinct low facial tubercle, yellow with ventrolateral dark vitta above genal suture, lighter medially, yellow pilose; gena yellow, yellow pilose; lunule and frontal triangle yellow, black pilose; vertical triangle dark anteriorly, orange posteriorly, black pilose; antenna orange, arista orange; holoptic, eye bare; occiput black, golden yellow pollinose, yellow pilose.
Thorax: Scutum subshiny black, yellow pilose; postpronotum yellow, bare; scutellum yellow, black pilose, subscutellar fringe complete with yellow pile. Pleuron mostly black, except posterior anepisternum yellow on posterior half, katepisternum with dorsal yellow macula, and anepimeron yellow dorsally, sometimes anterior anepisternum yellowish; metasternum bare; calypter yellow; plumula yellow; halter yellow; spiracular fringes yellow. Wing: Wing membrane mostly hyaline, veins yellow; vein R4+5 strongly sinuate; entire microtrichose. Alula broad, microtrichose. Legs: Entirely yellow, with femur-tibia joints lighter, except metacoxa brownish.
Abdomen: slightly oval, terga 2-5 strongly margined. 1st tergum black; 2nd tergum black with 2 medial round yellow maculae, isolated by black areas; 3rd-5th terga orange-yellow, more orange posteriorly, with lateral margin entirely yellow; 3rd tergum with broad black fascia on posterior margin and with black medial vitta forming an inverted T; 4th tergum similar to 3rd, but posterior black fascia divided into two diffuse black macula, sometimes without fascia, medial vitta narrower; 1st sternum translucent; 2nd and 3rd sterna black with translucent area on anterior margin, lateral margins orange; 4th sterna orange, black medially, 5th sternum to genital segments orange.
FEMALE.
Similar to male except as follows: frons entirely yellow, orangish posteriorly, black and yellow pilose; 4th tergum with submedial, not on posterior margin, and with black medial vitta forming an inverted T (smaller than in 3rd tergum), 5th tergum orange with black inverted V-shaped macula.
Synonyms:
Asiodidea potanini Stackelberg, 1930: 225.
Brachyopa nikkoensis Matsumura, 1916: 233.
unless otherwise stated