Asiobaccha aquila Thompson & Mengual

Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), Journal of Natural History 50, pp. 2585-2645 : 2594-2596

Asiobaccha aquila Thompson & Mengual sp. nov.

( Figure 4a, b, e )

Description

Male: Head. Face with distinct facial tubercle, dark brown becoming orangish-yellow medially, densely silver pollinose, yellow pilose ventrally and black pilose dorsally ( Figure 4e ); gena dark brown to black with oral margin paler; lunule yellow, yellow also between antennal bases; frons protruded forward, black with anterior M-shaped yellow macula, black pilose, golden-brownish pollinose posteriorly, shiny black medially; vertical triangle narrow, isosceles (more than four times as long as broad), with the ocelli on the anterior half, black, black pilose; antenna orangish-yellow, black pilose; arista dark brown, bare; eye bare, holoptic; occiput black, grey-silver pollinose, yellowish-white pilose on ventral 2/3 and black pilose on dorsal 1/3.

Thorax. Scutum black, scarcely brown pollinose, yellow pilose; mesonotal fringe or collar well-defined on anterior part of scutum, with pale pile; postpronotum dark, bare; notopleuron black, densely yellowish-white pollinose, yellow pilose; postalar callus lighter in background colour; scutellum black, yellow pilose, with brown pollinose fascia on anterior margin, subscutellar fringe almost absent ( Figure 4a, b ). Pleuron mostly black, except posterior anepisternum lighter in background colour on posterior half, katepisternum with dorsal macula lighter in background colour, both areas densely yellowish-white pollinose; katatergum also whitish pollinose; anterior anepisternum yellow pilose on posterodorsal quarter, posterior anepisternum and meron yellow pilose, dorsal and ventral katepisternal pile patches broadly separated, metaepisternum yellow pilose ventrad to spiracle; metasternum bare; calypter dark yellow; plumula yellow; halter brown; posterior spiracular fringes yellow. Wing: membrane dark, infuscated, except basally and apically; stigma brown; extensively microtrichose, except cell R bare basal to vein RS, cell BM bare on basal 1/2, and cell CuP and anal lobe bare basally. Alula present, broader than costal cell, bare with microtrichia on anteroapical quarter. Legs: coxae and trochanters black, pro- and mesoleg yellow, yellow pilose; metafemur yellow but somewhat dark apically, metatibia and metatarsus black.

Abdomen. Petiolate, unmargined. Dorsum mainly black, yellowish-white pilose on terga 1 and 2, black pilose on the remainder; tergum 1 black; tergum 2 with two basolateral yellow maculae and lateral margins lighter; tergum 3 with two medial yellow subtriangular maculae on anterior half; terga 4 and 5 black ( Figure 4a, b ); male genitalia black. Female. Similar to male except for normal sexual dimorphism and as follows: face white pilose; frons black, with bluish iridescence medially, with anterior M-shaped yellow macula; frons white pilose, white pollinose.

Variation. Colouration of the metafemur is variable; some specimens have metafemur dark on apical 2/3 and other specimens have it mostly yellow.

Length (N = 4). Body, 11.0 – 16.0 (13.9) mm; wing, 9.5 – 13.0 (11.3) mm.

Geographical distribution

Species known from the Philippines.

Etymology

The specific epithet is derived from the Latin aquilus meaning dark coloured, blackish ( Brown 1956, p. 148). Species epithet is to be treated as adjective.

Differential diagnosis

Species with a broad alula, mostly bare, with terga 1 and 4 black, mesonotal fringe present and an infuscated wing. Similar to A. bimaculata and A. nubilipennis , but A. aquila has the metatarsus entirely dark and the scutellum black. The face is bright yellow for most A. bimaculata and A. nubilipennis , but it is a bit darker in A. aquila .

Type locality

Philippines: Luzon Island, Cordillera Administrative Region, Ifugao Province, Liwo , 8 km East from Mayoyao , 1000 – 1300 m, 16°58 ′ N, 121°13 ′ E .

Material examined

Type material. Holotype, male, deposited in the Bernice P. Bishop Museum (Honolulu, Hawaii, USA) and labelled: ‘ PHILIPPINES // Ifugao Prov., Liwo // 8 km E Mayoyao, 1000- // 1300 m, 25.V.1967 ’, ‘ H.M. Torrevillas // Collector // BISHOP MUSEUM ’, ‘ Episyrphus // sp. 74–26 // Det. // FCThompson 74’, ‘ USNMENT // 00890779 ’ [barcode] ‘ HOLOTYPE // Asiobaccha // aquila // des. X. Mengual 2014’ [red] (specimen photographed). Paratypes: PHILIPPINES: Ifugao Prov., Liwo, 8 km east from Mayoyao , 1000 – 1300 m, H.M. Torrevillas [1♂, ZFMK, USNMENT 00890797];..., Mayoyao, 1000 – 1500 m, 6 July 1966, H.M. Torrevillas [1♀, BPBM]; Mindanao Island, Bukidnon Prov., Mt. Katanglad ,, 1250 m, 4 – 9 December 1959, L.W. Quate [1♂, USNM, USNMENT 00890773]; Luzon Island, Camarines Sur Prov., Mt. Isarog, Pili , 600 – 800 m, 10 April 1965, H. M. Torrevillas [1♂, BPBM, USNMENT 00890811]; Luzon Island, Bataan Prov., Limay , R.C.M. McGregor [1♀, USNM, USNMENT 00891196]; Negros Oriental Prov., Mt. Talinas , 900 m, 29 June 1958, H.E. Milliron [1♀, BPBM, USNMENT 00890782]; Laguna Prov., Los Baños , March 1917, F.X. Williams [1♀, USNM, USNMENT 00890765]; Nueva Vizcaya Prov., Santa Fe, Imugan , 30 – 31 May 1987, C.K. Starr [1♀, USNM, USNMENT 00890810; 1♀, ZFMK, USNMENT 00890786].

Remarks

Some specimens were identified as Episyrphus 74–26 Thompson, in litt.

Figures

Figure 4. Asiobaccha aquila Thompson & Mengual sp. nov. a–b, e, holotype ♂. (a) dorsal view; (b) lateral view; (e) frontal view. Asiobaccha bicolor (Austen). c–d, f, holotype ♂. (c) Dorsal view; (d) lateral view; (f) frontal view. Scale bars: a–d = 2 mm; e, f = 1 mm.