Ischiodon scutellaris (Fabricius, 1805):252

Ischiodon is a genus with two recognized species, aegyptius (Wiedemann, 1830) and scutellaris. Ischiodon species have eye bare, basoflagellomere elongate, postpronotum bare, anterior anepisternum bare, parallel-sided abdomen, face and scutellum partly yellow, metaepisternum bare, scutum with a well-defined lateral yellow vitta, abdomen margined, vein R4+5 straight or nearly so, male metatrochanter with ventral calcar, and wing hyaline extensively bare.

New description:

MALE.

Head: Face with facial tubercle, yellow, pale pilose; gena yellow, yellow pilose; frontal triangle yellow, yellow pilose; vertical triangle black, black pilose; holoptic, eye bare; antenna orangish, basoflagellomere orange, darker dorsally; pedicel very short, basoflagellomere elongate, much larger than scape and pedicel together; arista submedial, orange-brown; occiput black, white pollinose, white pilose.

Thorax: Scutum shiny black with lateral broad yellow vitta, yellow pilose; postpronotum black, bare; notopleuron and supra-alar area yellow; postalar callus black; scutellum yellow, yellow pilose, subscutellar fringe complete with yellow pile. Pleuron mostly black, except posterior anepisternum yellow on posterior half, and katepisternum with dorsal yellow macula, yellow pilose; anterior anepisternum bare, metasternum bare; calypter yellow; plumula yellow; halter yellow; spiracular fringes yellow. Wing: Wing membrane hyaline, extensively bare, bare on basal 2/3 and only sparse microtrichose on apical 1/3. Alula broad, sparse microtrichose. Legs: Entirely yellow to orangish, except coxae and trochanters black, metatarsi brown, metafemur brownish apically and metatibia brown medially. Metatrochanter with ventral calcar.

Abdomen: Parallel-sided, terga 3 to 5 margined. Dorsum mainly black pilose except tergum 1 and anterior half of tergum 2. Tergum 1 black, yellow laterally; tergum black with two medial rounded yellow maculae; terga 3 and 4 black with curved yellow fascia, emarginated on posterior margin (sometimes tergum 4 orangish); tergum 5 and posterior ones orange; sterna yellow-orange, sternum 2 with medial black macula; male genitalia greatly enlarged.

Ischiodon scutellaris (Fabricius, 1805).

Fabricius, J.C. (1805) Systema antliatorum secundum ordines, genera, species... xiv + 15-372 + [1] + 30 pp. C. Reichard, Brunsvigae [=Brunswick].

Synonyms:

Syrphus coromandelensis Macquart, 1842: 149.

Syrphus splendens Doleschall, 1856: 410.

Syrphus erythropygus Bigot, 1884: 87.

Ischiodon trochanterica Sack, 1913: 6.

Epistrophe platychiroides Frey, 1946: 164.

Syrphus ruficauda Bigot, 1884: 96.

Syrphus nodalis Thomson, 1869: 497.

Scaeva scutellaris Fabricius, 1805: 252.

Sphaerophoria annulipes Macquart, 1855: 116.

Melithreptus novaeguineae Kertesz, 1899: 178.

Epistrophe magnicornis Shiraki, 1963: 141.

Sphaerophoria macquarti Goot, 1964: 220.

Ischiodon boninensis Matsumura, 1919: 128.

Melithreptus ogasawarensis Matsumura, 1916: 23.

Ischiodon penicillatus Hardy, 1952: 363 [nomen nudum].

Similar to I. aegyptius, although this species is found in Afrotropical, including Madagascar, Réunion
and South-West Palaearctic (North Africa, Southern Spain, Madeira and Canary Islands).

This genus has been always related with Simosyrphus, as mentioned by Vockeroth (1969). Rotheray and Gilbert (1999) reported Ischiodon as sister group of the genus Scaeva in their analysis based on larval characters. In 2006, Laska et al. combined Ischiodon as junior synonym of Simosyrphus based on larval and molecular evidences.

Later, Mengual et al. (2008) reported the genus Ischiodon (as Simosyrphus) as sister group of Scaeva. Mengual (in litt.) using molecular characters recovered the non-monophyly of the group Ischiodon + Simosyrphus. Thus, we here accept them as two different genera.

Described from Tamil Nadu (India), Ischiodon scutellaris ranges from Iran, Turkey to Japan, south to India and Australia. It is also found in some Pacific Islands except Hawaii.