Ulia poecilogastra
Description
Body length: 3.0 mm without head (var.: 2.9-3.7); wing length: 3.2 (var.: 2.7-2.9) mm.
Male coloration and vestiture: frons shiny black, ocellar triangle and orbital plates shiny black, lunule brown, basoflagellomere black (var.: basomedially yellow), face black, palpus black; thorax with mesonotum subshiny black, scutellum and pleura same except for shiny spots on an- and katepisternum, wing hyaline, veins yellow, brown spot at tip of vein R1 present, calypter brown with brown margin and brown hairs, halter black, legs black except for orange basitarsi; abdomen with T1-2 and T5 shiny black except for silvery microtomentose subanterior band and posterolateral margin of T2 and anterior margin of T5; T3-4 silvery microtomentose except for row of black dots at hind margin. Female coloration and vestiture: calypter hyaline with brown margin and brown hairs, halter black, abdomen with T2-5 shiny to subshiny black.
Morphology. Head: frons with 2+1 (var.: 1) orbital and 2 frontal setae, anterior frontal seta ? (var.: slightly medioreclinate). In males frons ?x (var.: 2.9x) as wide at posterior margin than at base of antenna, arista about ?x (var.: 5.8x) as long as basoflagellomere wide, pubescence on arista ? (var.: very short), posterior eye margin with emargination (var.: notch (4oc) and emargination (2oc)). Female posterior eye margin with notch (4oc) and emargination (2-3oc).
Thorax: 1 dc, 0 prsc, 1 pprn, 1 prs, 2 keps setae, posterior prsc less than 0.8x as long as posterior dc, seta between posterior prsc and posterior dc absent. Wing with vein R4+5 and M1 converging (2.8-3.1), and ultimate section of vein M1 1.9x as long as penultimate section. Fore femur normal setulose, tibial organ present.
Male abdomen: Posteromedial triangular projection of T1 into T2 present. Tergal chaetotaxy: T2 anterolateral corner with more than 3 lines of setae, T2-5 black parts with some fine setulae, some longer setulae at tip of T5. S5 0.8x as long as wide, 1.5x as long and 1.9x as wide as S4, posterior margin only slightly indented, setulose with short setae and longer setae along posterior margin. Male genitalia with apical seta on cercus not longer than epandrial setae, 1 seta on subepandrial plate, surstylus 0.5x as long as epandrium high, dilated apically (1.4x), very broad, 1.3x as long as wide, with posteroapical indentation, structure of lateral surface smooth, medial surface without setulae.
Special characters: proboscis elongated with labella 2.5x as long as palpus and 1.2x as long as vertical eye diameter, female with long lunule, ventral tip of lunule reaching distal half of basoflagellomere (var.: male tip of lunule reaches middle of pedicel), head and thorax finely sculptured (var.: frons sculptured to a larger extent in females than in males), female hindleg slightly enlarged, wing plane nearly without microtrichia.
Male coloration and vestiture: frons shiny black, ocellar triangle and orbital plates shiny black, lunule brown, basoflagellomere black (var.: basomedially yellow), face black, palpus black; thorax with mesonotum subshiny black, scutellum and pleura same except for shiny spots on an- and katepisternum, wing hyaline, veins yellow, brown spot at tip of vein R1 present, calypter brown with brown margin and brown hairs, halter black, legs black except for orange basitarsi; abdomen with T1-2 and T5 shiny black except for silvery microtomentose subanterior band and posterolateral margin of T2 and anterior margin of T5; T3-4 silvery microtomentose except for row of black dots at hind margin. Female coloration and vestiture: calypter hyaline with brown margin and brown hairs, halter black, abdomen with T2-5 shiny to subshiny black.
Morphology. Head: frons with 2+1 (var.: 1) orbital and 2 frontal setae, anterior frontal seta ? (var.: slightly medioreclinate). In males frons ?x (var.: 2.9x) as wide at posterior margin than at base of antenna, arista about ?x (var.: 5.8x) as long as basoflagellomere wide, pubescence on arista ? (var.: very short), posterior eye margin with emargination (var.: notch (4oc) and emargination (2oc)). Female posterior eye margin with notch (4oc) and emargination (2-3oc).
Thorax: 1 dc, 0 prsc, 1 pprn, 1 prs, 2 keps setae, posterior prsc less than 0.8x as long as posterior dc, seta between posterior prsc and posterior dc absent. Wing with vein R4+5 and M1 converging (2.8-3.1), and ultimate section of vein M1 1.9x as long as penultimate section. Fore femur normal setulose, tibial organ present.
Male abdomen: Posteromedial triangular projection of T1 into T2 present. Tergal chaetotaxy: T2 anterolateral corner with more than 3 lines of setae, T2-5 black parts with some fine setulae, some longer setulae at tip of T5. S5 0.8x as long as wide, 1.5x as long and 1.9x as wide as S4, posterior margin only slightly indented, setulose with short setae and longer setae along posterior margin. Male genitalia with apical seta on cercus not longer than epandrial setae, 1 seta on subepandrial plate, surstylus 0.5x as long as epandrium high, dilated apically (1.4x), very broad, 1.3x as long as wide, with posteroapical indentation, structure of lateral surface smooth, medial surface without setulae.
Special characters: proboscis elongated with labella 2.5x as long as palpus and 1.2x as long as vertical eye diameter, female with long lunule, ventral tip of lunule reaching distal half of basoflagellomere (var.: male tip of lunule reaches middle of pedicel), head and thorax finely sculptured (var.: frons sculptured to a larger extent in females than in males), female hindleg slightly enlarged, wing plane nearly without microtrichia.
Diagnosis
Differs from congeners in the silvery pattern of the male abdomen in the combination with the presence of 3 orbital setae.
Discussion
All the recently collected specimens of this species have only 1 orbital seta, while the type specimens have 3 according to the original description. However since the head of the male type is lost and the female hasn’t got any setae on the frons left, this character can’t be verified. I refrain from describing a new species because the difference in the number of orbital setae is most likely a variation within the species.
In SMT there is 1 male syntype with head and one wing missing and 1 female syntype with head glued to thorax, thorax broken open and one wing missing. The female was labeled as lectotype by A. L. Serra in 1991 and the male as paralectotype. However, this lectotype designation has not been published so far and is not valid.
Distribution
Southern America: Central America (Costa Rica present); Western South America (Bolivia present, Peru present)
Citation
Neotropical catalog (Sabrosky 1973: Family Milichiidae 75: 12 pp: 7)
fig. of wing, male genitalia, Costa Rica
Bolivia, Costa Rica (Hennig 1939: Beiträge zur Kenntnis des Kopulationsapparates und der Systematik der Acalyptraten. II. Tethinidae, Milichiidae, Anthomyzidae und Opomyzidae. – Arb. morph. taxon. Ent. Berl. 6: 81-94: 85)
fig. of head, wing, male abdomen (Becker 1907: Die Dipteren-Gruppe Milichiinae. – Annls hist.-nat. Mus. natn. hung. 5: 507-550: 544)