Betasyrphus serarius (Wiedemann, 1830):128

Betasyrphus species have face densely gray pollinose; eye densely and uniformely pilose; scutum black, with at most a poorly defined dull yellow pollinose lateral vitta; katepisternal pile patches separated posteriorly; abdomen margined; metasternum bare; metaepisternum bare; abdominal maculae yellow or grayish, always very densely pollinose.

Synonyms:

Syrphus serarius Wiedemann, 1830: 128.

New description:

MALE.

Head: Face with small facial tubercle, yellow with medial dark vitta not reaching antennal bases, from oral margin to tubercle, black ventrolaterally, gray pollinose laterally, black pilose; gena dark, yellow pilose; lunule shiny black; frontal triangle black densely yellowish-gray pollinose, black pilose; vertical triangle black, black pilose; holoptic, eye pilose; antenna black, arista black; occiput black, silver pollinose, mainly yellow pilose, white pilose ventrally.

Thorax: Scutum black, entirely golden pollinose, yellow pilose with black pile on supra-alar area and postalar callus; postpronotum bare; scutellum yellow, black pilose, subscutellar fringe complete with yellow pile. Pleuron black, densely gray pollinose, white pilose; metasternum bare; calypter whitish; plumula white; halter whitish-yellow; spiracular fringes white. Wing: Wing membrane hyaline; microtrichose, with broad bare areas basally (cells R1 and BM). Alula broad, microtrichose. Legs: Entirely brownish-orange except coxae and trochanter darker, femora dark brown basally.

Abdomen: slightly oval, 3rd and 4th terga vaguely margined. Dorsum mainly black, yellow pilose dorsally and laterally except terga 2-5 black pilose on posterolateral 1/5-1/4; 1st tergum black, bluish pollinose; 2nd tergum black with two medial, narrow, orangish-yellow fasciate maculae covered by dense gray pollinosity, sometimes joined medially; 3rd and 4th terga black with submedial orangish-yellow fascia, slightly broadened laterally, covered by dense gray pollinosity; 5th tergum black with two subbasal gray pollinose maculae.

FEMALE.

Similar to male except as follows: face black and yellow pilose; frons golden pollinose medially, shiny black posteriorly reaching vertical triangle; 2nd tergum with the two maculae joined medially forming a narrow fascia.

Betasyrphus serarius (Wiedemann, 1830).

Wiedemann, C.R.W. (1830) Aussereuropaische zweiflugelige Insekten. Zweiter Theil. Schulz, Hamm. xii + 684 pp., 5 pls.

Oriental species known from China, Buru, New Guinea (Irian Jaya), and it is also found in Australia (NSW, QLD).