Citrogramma shirakii, Mengual, 2012

Mengual, Ximo, 2012, The flower fly genus Citrogramma Vockeroth (Diptera: Syrphidae): illustrated revision with descriptions of new species, Zoological Journal of the Linnean Society 164 (1), pp. 99-172 : 163-164

CITROGRAMMA SHIRAKII MENGUAL SP. NOV.

Xanthogramma fumipenne of Shiraki, 1930 (in part).

Description

Male: Head: Face with small facial tubercle, gradually sloping dorsally, more abrupt ventrally, entirely yellow, yellow pilose except black pilose dorsally; gena yellow, yellow pilose with some brown hairs on genal suture, white pollinose posteriorly; holoptic; lunule dark yellow; frontal triangle yellow with anteromedial black macula, black pilose; vertical triangle black, slightly longer than eye contiguity, black pilose; ocelli reddish; antenna orangish brown, black pilose on scape and pedicel; basoflagellomere dark dorsally; arista black; occiput black, golden pollinose, white pilose on ventral half, yellow pilose on dorsal half.

Thorax: Scutum black, black and yellow pilose dorsomedially, with lateral yellow vitta; postpronotum yellow; notopleuron yellow continuing until scutellum, yellow pilose; postalar callus yellow, black pilose; scutellum yellow, black pilose, with complete subscutellar fringe with black hairs. Pleuron mostly yellow, except posterior anepisternum black on anterior third, katepisternum black with dorsal yellow macula, meron black, posterior anepimeron black dorsally, entirely yellow pilose, white-grey pollinose on black areas; metasternum pilose; calypter yellow, blackened dorsally with dark and yellow hairs on margin; plumula yellow; halter yellow; spiracular fringes yellow.

Wing: Wing membrane light brown, entirely microtrichose. Alula microtrichose, broad, broader than cell BM.

Legs: Coxa and trochanter yellow except mesocoxa and mesotrochanter dark; pro- and mesofemur yellow; pro- and mesotibia yellow; pro- and mesotarsus brown-dark; metafemur yellow, black on distal quarter; metatibia and tarsus black.

Abdomen: Figure 78 . Parallel-sided, dorsum mainly black, black pilose dorsally and laterally except tergum 1 yellow pilose laterally and tergum 2 yellow pilose laterally on anterobasal half; tergum 1 black, yellow laterally; tergum 2 black with two mesolateral round/subtriangular yellow maculae, laterally extending forward to anterolateral tergal margin (like ‘golf club’-shaped spots), yellow lateral margin on anterior fifth; terga 3 and 4 black with broad yellow fascia, about one third to two fifths of tergum length; tergum 5 black with broad yellow fascia, about half of tergum length; terga 2, 3, 4, and 5 with anterior narrow black fascia; sterna yellowish, black and yellow pilose; male genitalia large, as in Figure 152 ; surstylus with long erected yellowish hairs.

Female: Unknown.

Length (N = 1): Body, 10.1 mm; wing, 8.8 mm.

Geographical distribution: Taiwan.

Etymology: The specific epithet honours Tokuichi Shiraki (1882–1970), a Japanese entomologist who worked mainly on Diptera and described new species of Citrogramma in his comprehensive review of Syrphidae occurring in the Sino-Malayan subregion, including the Indochinese peninsula, Taiwan, and Japan, as well as Palaearctic eastern China and Siberia ( Shiraki, 1930). Species epithet to be treated as a noun in apposition.

Differential diagnosis: Citrogramma shirakii can be easily separated based on male genitalia. There is no other species with surstylus with long yellow hairs except C. hervebazini , but that species has yellow face with medial black vitta, scutellum with black macula, metafemur black, and halter capitulum black. Male genitalia of C. shirakii and C. hervebazini are very similar (see Figs 151, 152 ), but C. hervebazini has larger superior lobes and surstylus with a larger basoanterior protuberance bearing long yellow hairs. Although C. shirakii has male genitalia similar to C. hervebazini , it keys out with C. frederici sp. nov., which also has yellow face, posterior anepisternum partly black anteriorly, metafemur yellow basally, and frontal triangle more than 90°. Citrogramma shirakii differs from C. frederici in male genitalia and wing microtrichia.

Remarks: Shiraki (1930) originally identified the holotype specimen as C. fumipenne ( Matsumura, 1916) . Citrogramma shirakii differs from C. fumipenne by having posterior anepisternum partly black and anterior anepimeron yellow; whereas C. fumipenne has anepisternum yellow and anepimeron black except dorsomedial portion. Additionally, the genitalia of C. fumipenne are very small compared with the one of C. shirakii and with no long hairs on surstylus.

Holotype male deposited in the Natural Resources Inventory Center (National Institute for Agroenvironmental Sciences, Ibaraki, Tsukuba, Japan) and labelled: ‘Formosa/Karenko, -19/VII 20–VIII 4./T. Okuni,/J. Sonan,/K. Miy., M. Yosh.’ ‘ Xanth. Mats / fumipenne /Det. T. Shiraki’ [handwritten except third line] ‘ HOLOTYPE / Citrogramma / shirakii / det. X. Mengual 20 09 ’ [red, second and third lines handwritten].

Type locality: TAIWAN: Hualien County, Hualien City (= Karenko), 23°58′20′′N, 121°36′23′′E .

Material examined: Type material. Holotype, as above.

Figures

Figures 76–87. 76–77, Citrogramma clarum: 76, dorsal view of male abdomen; 77, dorsal view of female abdomen. 78, Citrogramma shirakii, dorsal view of male abdomen. 79, Citrogramma frederici, dorsal view of male abdomen. 80–84, Citrogramma chola: 80, lateral view of male head and pleuron; 81, dorsal view of male head; 82, dorsal view of female head; 83, dorsal view of male abdomen; 84, dorsal view of female abdomen. 85-87, Citrogramma citrinum: 85, dorsal view of male abdomen; 86, dorsal view of female head; 87, dorsal view of male head.

Figures 151–153. Male genitalia. 151, Citrogramma hervebazini (from Vockeroth, 1969): a, left lateral view, surstylus outlined only; b, superior lobe, lateral, outline only; c, sternum 9, superior lobes and aedeagal base, ventral view; d, left surstylus, lateral view. 152, Citrogramma shirakii, left lateral view. 153, Citrogramma quadricornutum (from Vockeroth, 1969): a, left lateral view (sternum 9 mostly hidden); b, superior lobe, lateral, outline only; c, sternum 9 and genitalia, left lateral view; d, tergum 9 and cerci, dorsal view; e, sternum 9, superior lobes and aedeagal base, ventral view; f, right surstylus, lateral view.