Milichiella frontalis
Differs from congeners in the brown microtomentose male T2-5 except for silvery microtomentose posterolateral margin of T2 and narrow to broad anterior margins of T3-5, which get broader laterally to build silvery lateral margin, and blueish silvery tip of T5.
Male coloration and vestiture: frons black, ocellar triangle and orbital plates brown microtomentose, lunule black, basoflagellomere black, face black microtomentose, palpus black; thorax with mesonotum slightly to normally brown microtomentose with shiny hue, scutellum and pleura same except for shiny spot on anepisternum, wing hyaline, veins brown, brown spot at tip of vein R1 absent, calypter light brown with dark margin, halter black, legs black; abdomen with T2-5 brown microtomentose except for silvery microtomentose posterolateral margin of T2 and narrow to broad anterior margins of T3-5, which get broader laterally to build silvery lateral margin; tip of T5 blueish silvery. Female coloration and vestiture: halter brown, abdomen with T2-5 subshiny, slightly brown microtomentose.
Morphology. Head: frons with 2+1 orbital and 2 frontal setae, anterior frontal seta medioclinate. In males frons 2.3-2.5x as wide at posterior margin than at base of antenna, arista about 6.0x as long as basoflagellomere wide, pubescence on arista very short, posterior eye margin with narrow notch (3-4oc) and emargination (2oc).
Thorax: 3+1 dc, 3 (female: 1) prsc, 1 pprn, 1 prs and row of short setae, 2+0.8 keps setae, posterior prsc about as long as posterior dc, seta between posterior prsc and posterior dc small. Wing with vein R4+5 and M1 weakly converging (1.5), and ultimate section of vein M1 3.2x as long as penultimate section. Fore femur slightly stronger setulose, tibial organ absent.
Male abdomen: posteromedial triangular projection of T1 into T2 present. Tergal chaetotaxy: T2 anterolateral corner with 2-3 lines of setae, T1 setulose, T2-5 silvery parts bare, black parts setulose, lateral margins with long setae, T5 with row of setae anterior to silvery tip. S5 about 1.2x as wide as long, about 3.1x as wide and 1.3x as long as S4, crescent shaped, setulose). Male genitalia with apical seta on cercus not longer than epandrial setae, 1 seta on subepandrial plate, surstylus 0.2-0.3x as long as epandrium high, slightly bent anteriorly, about as long as wide, not dilated apically, structure of lateral surface smooth, medial surface without setulae.
Special characters: orbital plate extends into frons as acute medioventral tip; setae much shorter in female.
Body length: 2.5 mm; wing length: 2.8 mm.
Species in the frontalis-group are characterized by the combination of male thorax slightly brown microtomentose, 3+1 dc, bent tip of T5 bluish silvery microtomentose. It is quite possible that all three species currently belonging to this group represent varieties of one species. The amount of male silvery microtomentum in Milichiella frontalis varies quite considerably between specimens and the difference between the colour of the male abdomen of some M. frontalis (e.g. Chile: El Coigo) and the lectotype of M. montanum is rather small. At the same time the difference between M. montanum and M. concavum is small, too.