Citrogramma citrinum (Brunetti, 1923):95

Species with face entirely yellow, posterior anepisternum black anteriorly, scutellum with a diffused brownish macula and metafemur yellow on basal 1/3–1/2. Citrogramma citrinum is similar to Citrogramma chola, whose males have the frontal triangle narrow with an angle between eyes less than 90°. The differences with C. chola are that C. citrinum has notopleuron entirely yellow pilose and anepimeron black. Males of C. citrinum have frontal triangle with a medial brownish orange macula, 3rd abdominal tergum with a yellow fascia with subparallel margins and slightly emarginate posteriorly, and 4th tergum with a yellow fascia with subparallel posterior margin to posterior tergal margin. Females of C. citrinum have lunule yellow, frons yellow medially and 4th tergum with a yellow fascia slightly widening to lateral margins; while females of C. chola have frons yellow with an anteromedial dark triangular macula and lunule dark.

Adapted from original description (Brunetti 1923).

♂ ♀. Head: vertical triangle in ♂ very small, black with black pile and ruby-red ocelli; eyes closely contiguous for a considerable distance; dorsal and middle facets enlarged nearly as much as in Lasiopticus (=Scaeva); frons and face orange-yellow, a large triangular space above antennae more brownish-orange; frons with moderately thick short black pile; face with very sparse pale yellow pile; mouth-border narrowly rather orange; proboscis black and orange. Antennae brownish-orange, dorsally darker. Gena pale orange. Occipital margin yellowish-grey with yellow fringe and (in ♂ only) black short pile behind vertex. In ♀, head deep chrome-yellow, vertex rather narrowly black, the colour carried very narrowly a little way down eye-margins; pile of frons much less dense on dorsal part, that of face extremely fine, almost invisible.

Thorax: scutum moderately shining black, with (especially in the ♀) a deep blue reflection in certain lights; in addition, centre of scutum from anterior to posterior margin narrowly dusted with greenish-grey, in which (in ♀) traces of a pair of narrow median brownish vittae can be seen in perfect specimens. Side margins broadly and conspicuously orange-yellow from prostpronotum to scutellum. Sides of thorax, black, with two squarish yellow maculae immediately below the postpronotum, thus forming three subequal maculae in a vertical row; a large, oblong macula, placed vertically, on mesopleura, connecting the side marginal vitta of the dorsum with a horizontal one on the katepisternum, which latter macula is contiguous with two others (forming a slightly curved raw of three), more or less oblong, the last one lying just behind and below the wing-base; all the maculae very clear cut and bright orange-yellow. In ♀ they are considerably fused, mainly through the large size of the anpisternal macula, which extends to nearly all the others, so that the whole sides of the thorax are practically unicolorous, leaving only the lower surface of the thorax black. Pilosity of thorax brownish-yellow on dorsum, bright yellow or orange-yellow towards sides, paler yellow on pleurae; some stiff black pile on hind corners of dorsum. Scutellum deep lemon-yellow, more or less translucent and often with centre darkened; pilosity wholly black, long and copious. Pilosity of dorsum of thorax in ♀ blackish-brown. Legs orange-yellow. Metafemur on apical half, metatibia and all tarsi, black; ventral side of metatarsus with golden-yellowpile. Pilosity of legs, mainly confined to a little soft, pale yellow pile behind and below the profemur and the basal half of metafemur; black pile on black parts of metalegs. Wing pale yellowish-grey; stigma brownish-yellow; halters orange.

Abdomen moderately shining black, with a pair of well separated orange-yellow maculae on 2nd tergum, elongate, rather curved, the inner ends rounded, the outer ends passing their full width over side margins on anterior corners; 3rd and 4th terga with an unbroken yellow fascia on each, barely appreciably emarginated in middle on both anterior and posterior margins; each macula lying across centre of tergum and passing its full width over lateral margins; the second one of the fascia placed a trifle nearer the anterior than the posterior margin and very slightly widening on lateral margins; 5th tergum mainly orange, but with a black triangle in middle of posterior margin in ♂, and with posterior margin all black in ♀. Pile of abdomen wholly black except at sides near the base, where it is long, copious and yellow. Sterna yellowish, blackish towards genitalia. Genitalia in ♂ dull orange with long black pile.

Brunetti (1923) described Xanthogramma citrinum from Indian material (3 males and 2 females) and mentioned another male, in the Indian Museum, that might possibly represent a different species based on some morphological differences. Hervé-Bazin (1923b) transferred X. citrinum to Olbiosyrphus, explaining the differences between the two genera. Curran (1928), in his revision of flower flies from the Malay Peninsula, transferred this species to the genus Syrphus Fabricius. Finally, Vockeroth (1969) placed this species in his new genus Citrogramma.

Citrogramma citrinum (Brunetti, 1923).

Brunetti E. 1923. Diptera. Pipunculidae, Syrphidae, Conopidae, Oestridae. In: Shipley AE, ed. Fauna of British India including Ceylon and Burma, vol III. London, Taylor Francis, 424 pp. + 6 pl.

Body lenght: 9-12 mm.

Species cited from China, Thailand, India and the Malay Peninsula (Pahang and Perak States).