From original description (Mengual 2011)
MALE.
Head. Face with facial tubercle, gradually sloping dorsally, more abrupt ventrally, entirely yellow, yellow pilose, dark brown pilose dorsolaterally; gena yellow, yellow pilose posteriorly with brown pile on genal suture, white pollinose posteriorly; holoptic; lunule yellow; frontal triangle yellow, dark brown pilose; vertical triangle black, black pilose; ocelli reddish; antenna orangish, black pilose on scape and pedicel; basoflagellomere dark dorsally and distally; arista dark; occiput black, silver pollinose, white pilose on ventral 1/2, yellow pilose on dorsal 1/2.
Thorax. Scutum blackish brown with dorsomedial area uniformly bluish grey pollinose with certain metallic iridescence, with lateral broad yellow vitta, yellow pilose with black pile on posterior 1/2 and on postalar callus, with two or three black pile on notopleuron; postpronotum yellow; notopleuron yellow continuing to scutellum, with postalar callus entirely yellow; scutellum yellow, black pilose, subscutellar fringe complete with brown pile. Pleuron mostly yellow, except katepisternum black ventrally and meron dark, entirely yellow pilose; metasternum pilose; calypter yellow, brownish dorsally with long yellow pile and short black pile on margin; plumula yellow; halter yellow; spiracular fringes yellow.
Wing. Wing membrane hyaline, entirely microtrichose. Alula microtrichose, broad, broader than cell BM.
Legs. Coxa and trochanter yellow, yellow pilose; pro- and mesofemur yellow, mainly black pilose, yellow pilose basally; pro- and mesotibia yellow, black pilose; pro- and mesotarsus brown; metafemur yellow on basal 1/2–2/3, brown/dark on distal 1/3–1/2; metatibia brown with medial yellow annulus; metatarsus dark brown, black pilose.
Abdomen. Parallel-sided, slightly oval, 3rd, 4th and 5th terga vaguely margined. Dorsum mainly black or dark brown, black pilose dorsally and laterally except 1st tergum yellow pilose laterally and 2nd tergum yellow pilose laterally on anterobasal 1/2 and dorsally on yellow maculae; 1st tergum black, yellow laterally; 2nd tergum black with 2 mesolateral round yellow maculae, extended forward laterally to anterolateral tergum margin (like “golf club” shaped spots), yellow lateral margin on anterior 1/2; 3rd and 4th terga black with broad yellow fascia, about 1/3–2/5 of tergum length; 5th tergum black with very broad yellow fascia having posterior margin curved; sterna mainly yellow, yellow and black pilose; male genitalia small.
FEMALE. Similar to male except for normal sexual dimorphism and as follows: face entirely yellow pilose, frons yellow, dark brown pilose; ocellar triangle black; occiput yellow pilose. Scutum yellow pilose, with some black pile posteriorly close to scutellum and on postalar callus, but lesser black pile than in male; notopleuron yellow pilose; katepisternum grey pollinose on black ventral area. Pro- and mesobasitarsomere yellowish basally, brown distally; metafemur yellow on basal 2/3, dark brown on distal 1/3; 2nd abdominal tergum with 2 “golf club” shaped yellow maculae joined medially forming a yellow fascia but of different shape than those on 3rd and 4th terga; 4th tergum with yellow fascia broader at lateral margin; 5th tergum with yellow lateral margin on basal 4/5.
Variation. In all specimens the yellow annulus of the metatibia is difficult to see because most of them have brownish metatibia, so the contrast is little. Paratype male from Philippines has abdomen compressed anteroposteriorly; thus, abdominal characters are difficult to see but it seems that 5th tergum has 2 triangular yellow maculae instead of a yellow fascia.
Females have small differences among them. Some specimens have little black pile on postalar callus but others do not. The most variant female is the one from Pahang Province, previously a paratype of Citrogramma difficile. Its frons matches the description but it has a very small black fascia posteriorly on lateral margin. Consequently it was not included as paratype. The other male from India was not included in the type series because its head is lost.
Synonyms: Olbiosyrphus clarum of Hervé-Bazin 1923a, 1923b (in part); Syrphus difficilis of Curran 1928 (in part); Syrphus clarus of Curran 1931b (in part).
Citrogramma amarilla Mengual, 2011.
Mengual, X. (2011) The flower fly genus Citrogramma Vockeroth (Diptera: Syrphidae): illustrated revision with descriptions of new species. Zoological Journal of the Linnean Society, in press.
unless otherwise stated