Mixogaster conopsoides Macquart, 1842:74

Mixogaster is a group of petiolate Microdon flies restricted to the New World. They are distinguished from all other petiolate Microdon groups by 1) lacking an appendix on vein R4+5; 2) having a reduced and bare metasternum; 3) unarmed scutellum; and 4) usually an appendix on vein M extending in cell R4+5. Some earlier authors more broadly interpreted the concept of this genus and described species now placed elsewhere [aphritina Thomson = Paramixogaster, bellula Williston = Pseudomicrodon, cinctella Sack = Paramicrodon, claripennis Hine = Pseudomicrodon, nigripennis Sack = Paramicrodon, variegata Sack = Paramixogaster, and vespiformis Brunetti = Paramixogaster] (Cheng and Thompson 2008). Hull (1954) provided a revision of the genus.

Mixogaster conopsoides Macquart, 1842.

Macquart, P.J.M. (1842) Dipteres exotiques nouveaux ou peu connus. Tome deuxieme. 2e partie. Mémoires de la Société Royale des Sciences, de l'Agriculture, et des Arts à Liège 1841(1), 65-200, 22 pls.

From original description (Macquart 1842) in French.

Niger. Abdominis incisuris flavis. Alarum limbo externo fuscano.

♀. Face jaune, à petits poils blanchâtres; une bande longitudinale noire, rétrécie inférieurement et n'atteignant pas l’épistome. Front noir; une bande transversale jaune au bord du sillon: une petite tache jaune, carrée, au vertex. Antennes noires. Thorax noir; une petite bande fauve, longitudinale, de chaque côté, et une bande dorsale fauve; écusson brun. Abdomen noir; deuxième segment à base brune et bord postérieur jaune, ainsi que les bords latéraux; troisième à bord postérieur jaune; un peu de jaune au bord postérieur du quatrième. Pieds fauves; cuisses un peu brunâtres; jambes à moitié postérieure brunâtre, du côté intérieur. Ailes un peu jaunâtres ; bord extérieur brunâtre , formé par le bord brun des premières nervures longitudinales; première cellule postérieure à deux petits appendices au bord postérieur et un à l’intérieur.

New description:

FEMALE.

Head: Face straight, without tubercle, yellow with medial brown vitta broadening medially, with long yellow pile; gena narrow, yellow; lunule dark brown; frons yellow with medial dark brown macula dorsad to antennal base, dark pilose; dichoptic, eye bare; vertical triangle yellow with black macula between ocelli, black pilose; antenna dark, basoflagellomere micropilose, as long as scape and more than 3 times longer than pedicel; occiput narrow, a bit broader dorsally, yellow pilose.

Thorax: Scutum dark brown with dorsomedial broad yellow vitta and lateral margins broadly yellow, mainly with appressed yellow pile with some black pile medially; scutellum small, rounded, yellow with medial brown macula, yellow pilose, subscutellar fringe absent; subscutellum large. Pleuron mostly yellow, with meron, katepimeron and anterior part of anepimeron, anterior anepisternum and posterior anepisternum brownish-orange; anterior anpisternum pilose; metasternum bare; calypter yellow; plumula absent; halter yellow; spiracular fringes brownish. Wing: Wing membrane yellowish; extensively microtrichose, except cell CuP bare with some microtrichia apically, anal lobe abre basally and cell R4+5 bare between vein spurious and CuA1; vein R4+5 withou appendix; vein M with small appendix into cell R4+5; vein M1 sigmoid. Alula broad, bare, microtrichose apically. Legs: Entirely brownish, yellowish pilose; metatibia with two media incisions or depressions.

Abdomen: Petiolate, minimum width of tergum 2 narrower than thorax, concave, only tergum 2 margined. Dorsum mainly dark brown, terga 2, 3 and 4 with yellow fascia on posterior margin; tergum 2 with two medial yellow maculae on lateral margins.

Adapted from Hull (1954).

This species clearly possesses a bright, complete, yellow, medial vitta down the mesonotal disc, with the sides broadly yellow; the lateral margins, including postpronotum and postalar callus, give the thorax its distinctive trivittate appearance.

Body lenght: 12.4 mm (Macquart 1842).

Neotropical species known from Colombia and Brazil.