Pseudeurybata stigmatica Hennig

Marshall, S. A., 2016, Revision of the genus Pseudeurybata Hennig (Diptera, Micropezidae, Taeniapterinae), Zootaxa 4132 (2), pp. 254-268 : 264-266

Pseudeurybata stigmatica Hennig

Figs. 38–44

Pseudeurybata stigmatica Hennig, 1935: 28

Description. 15–17mm. Head with epicephalon shining along lateral margin but otherwise silvery microsetulose and contrasting with the dull orange frontal vitta. Frontal vitta broad, indistinguishable from orbital strips anterior to ocelli, gradually tapered to postocellar setae behind. One lower fronto-orbital seta. Arista black, finely pubescent at base only. Clypeus entirely shining.

Thorax with a characteristic depression crossing the middle of the presutural part of the mesonotum; colour reddish brown with lateral and dorsolateral patches of silvery pruinosity and indistinct longitudinal mesonotal vittae. Anepisternum, but not katepisternum, with sparse small dark setae. Posterior rows of katepisternal setae golden. Femora brown with contrasting black apices, tibia and tarsi dark brown to black, hind tibia paler.

Wing clear except for darkly pigmented apex; halter knob reddish brown.

Abdomen of female with pleuron cream yellow ventrally, slightly darker on on dorsal half or slightly more. Oviscape broad, reddish and microsetulose basally, tapered and shining black distally, 5X length of T6. Both spermathecal ducts ringed with striae, paired spermathecae very large, sausage-like; single spermathecae similar but much smaller.

Male abdomen pale except for a dark pleural sac covering the upper third of pleuron three; S5 with genital fork simple, with two long, slightly converging arms and a pair of subquadrate inner basal tubercles, each with 2–3 stout teeth. Distiphallus broad, terminating in a dense phallic bulb almost half as long as basal part of phallus.

Type material. Holotype (♀, AMNH). PANAMA, Barro Colorado Island, Canal Zone, 21.ii.29, C.H. Curran.

Non-type material examined. COSTA RICA San Juan de Penas Blañcas, San Ramon, Soltis Research Centre, 17.viii.2013, S.A. Marshall (1♀, 2♂, DEBU); Guanacaste, Estacion Pitilla, 9kmS Santa Cecillia, 700m, Apr.1994, Jan.1995 C. Moraga (1♀, 1♂ MNCR); Estacion Maritza, 13.Fe.1996 S. A. Marshall (1♂ MNCR), Puntarenas, Estacion Sirena, 1–100m, 5–23.April.1995, A. Picado (1♂ MNCR); Corcavado, 176m, 14.Dec.2000, K. Caballero (1♂ MNCR).

Distribution. Costa Rica, Panama.

Remarks. Pseudeurybata stigmatica is an unmistakable fly because of its unique wing pigmentation, leg pigmentation, and thoracic shape. It is also seems to be distinctive for its posture in the field, as several males were observed with mouparts extended far forward and one or both hind legs extended straight into the air ( Fig. 43 ). Females were observed to feed in a characteristic "abdomen up" pose similar to some Scipopus species ( Fig. 38 ).

Figures

FIGURES 38 – 44. Pseudeurybata stigmatica. 38, female feeding on debris on leaf surface; 39, female, characteristic stance; 40, spermathecae and associated structures; 41, male terminalia, lateral view; 42, apex of distiphallus to show phallic bulb, lateral view; 43, male, characteristic stance; 44, male genital fork, ventral view.