Allobaccha amphithoe (Walker, 1849):549

Allobaccha is a genus of the tribe Syrphini (subfamily Syrphinae). Allobaccha species have antenna short, shorter than head; face partially yellow; abdomen elongate, strongly petiolate (2nd tergum narrower than 3rd); calypter bare. Allobaccha has 2 main groups of species: one group with postpronotum bare, and a second group with postpronotum pilose.

Allobaccha amphithoe (Walker, 1849).

Walker, F. (1849) List of the specimens of dipterous insects in the collection of the British Museum. Part II, [iii]+231-484. [1849.04.21]; Part III: [iii]+485-687. [1849.06.30]; Part IV. Pp. [3] + 689-1172 + [2] [1849.12.08] British Museum (Natural History), London.

New description:

MALE.

Head: Face narrow with small facial tubercle, yellow with medial broad black vitta from antennae base to below tubercle but not reaching oral margin, yellow pilose; gena very narrow, yellow anteriorly and black posteriorly, yellow pilose; lunule brown; frontal triangle yellow with a medial black vitta covered by pollinosity on posterior half, whitish-yellow pilose, dense silvery pollinose on posterior half; vertical triangle black with a medial row of long yellow pile; holoptic, eye contiguity as long as scape and pedicel length together; antenna yellow, arista yellow basally and black apically; occiput black, silver pollinose, with a single row of withish-yellow pile.

Thorax: Scutum shiny black with lateral yellow vitta interrupted after transverse suture, yellow pilose; postpronotum yellow, bare; notopleuron yellow, yellow pilose; postalar callus yellow; scutellum yellow, yellow pilose, without subscutellar fringe. Pleuron mostly black, except posterior anepisternum black on posterior 2/3, katepimeron and katatergum yellow, and katepisternum with dorsal broad yellow macula; anterior anepisternum pilose; metasternum bare; metaepisternum pilose; calypter yellow, bare; plumula yellow; halter yellow, sometimes capitulum darkened; spiracular fringes yellow. Wing: Wing membrane mostly hyaline, 2nd costal cell and stigma dark brown, stigma darker; microtrichose except basal half of cell R posteriorly, cell BM (with few microtrichia apically) and cell CuP basally. Alula triangular, with apical extreme broader than 2nd costal cell, bare with few microtrichia anteriorly. Legs: Entirely yellow except coxae dark brown, metafemur and metatibia brown on apical half, metabasotarsomere brown on basal 2/3.

Abdomen: flat, elongate, strongly petiolate, 2nd tergum 3.5 times narrower than 4th tergum, 3rd tergum broadening abruptlyin the medial section; 1st and 2nd terga yellow pilose, the rest black pilose. 1st tergum yellow; 2nd tergum light brown to reddish with a subapical small yellow fascia; 3rd tergum black, light brown to reddish basally, with a medial semicircular arcuate yellow macula not reaching lateral margins; 4th tergum black with medial broad yellow macula with posterior margin emarginated and reaching anterior margin of the tergum; 5th tergum yellow with black lateral margins and medial black vitta not reaching posterior margin; sterna yellow, 3rd and 4th sterna with black fascia on posterior margin; male genitalia enlarged.

FEMALE.

Similar to male but differs as follow: fons yellow with a medial black vitta covered by pollinosity on posterior 2/3, whitish-yellow pilose, dense silvery pollinose on posterior 2/3 until ocellar triangle. Abdomen similar to male, a bit broader posteriorly.

Allobaccha was described by Curran (1928) as a subgenus of Baccha for species with pilose postpronotum. Smith and Vockeroth (1980; Catalogue of the Diptera of the Afrotropical Region) elevated Allobaccha to genus level.

Synonyms:

Baccha amphithoe Walker, 1849: 549.

Baccha pedicellata Doleschall, 1856: 411.

Baccha bicincta Meijere, 1910: 104.

Baccha flavopunctata Brunetti, 1913: 165.

Baccha fulvicostalis Matsumura, 1916: 226.

Shatalkin (1975a) related Allobaccha with Baccha and included it into her tribe Bacchini, but close to the Dideini (Didea, Eriozona, Megasyrphus, Asarkina, Episyrphus and Meliscaeva). Mengual et al. (2008) included 3 species of Allobaccha in their molecular phylogenetic analysis. Allobaccha was resoled as monophyletic and repeatedly placed as sister group of the tribe Paragini.

There are no larval prey or adult- visited flower reported for Allobaccha amphithoe. Nevertheless, larvae of other species of Allobaccha have been found feeding on Aphididae, Psyllidae, Chrysopa eggs (Neuroptera), Pseudococcidae, Lepidoptera larvae, Aleyrodidae, Cicadidae and Fulgoridae (for more details, see Rojo et al. 2003).

Oriental species ranging from Sri Lanka, India, Japan, Taiwan, south to Flores (Indonesia).