Milichiella pseudopuntiae has been collected in light and Malaise traps and reared from Opuntia (Platyopuntia), Opuntia occidentalis, Pachycereus sp., Myrtillocactus geometrizans and Echinocactus polycephalus (Cactaceae).
Differs from M. opuntiae in the less setulose postgena, mesonotum subshiny, and S5 less setulose and setulae shorter.
Male coloration and vestiture: frons subshiny black, ocellar triangle slightly brown microtomentose between ocelli, but tips and orbital plates shiny black, lunule black, basoflagellomere black, face silvery microtomentose, palpus black; thorax with mesonotum subshiny (very slightly brown microtomentose), scutellum and pleura slightly brown microtomentose except for shiny spot on an- and katepisternum, wing hyaline, veins brown, brown spot at tip of vein R1 absent, calypter hyaline with hyaline or light brown margin, halter black, legs black; abdomen with T2-5 black microtomentose except for shiny posterolateral margins of T2-4 and posterior 3/4 of T5. Female coloration and vestiture: halter base of knob yellow, rest brown, abdomen with T1-4 brown microtomentose dorsally, T5 shiny.
Morphology. Head: frons with 2 orbital and 3 frontal setae, middle frontal seta medioreclinate. In males frons 2.2x as wide at posterior margin than at base of antenna, arista about 3.0x as long as basoflagellomere wide, pubescence on arista very short, posterior eye margin without notch, gradually separating from head margin ventrally.
Thorax: 3+1 dc, 3+1, 4+1 prsc, 1 pprn, 1 prs and row of short setae, 1+0.8 or 2+0.8 keps setae, posterior prsc about as long as posterior dc, seta between posterior prsc and posterior dc absent. Wing with vein R4+5 and M1 converging (2.0), and ultimate section of vein M1 2.0x as long as penultimate section. Fore femur slightly stronger setulose, tibial organ absent.
Male abdomen: posteromedial triangular projection of T1 into T2 weak. Tergal chaetotaxy: T2 anterolateral corner with more than 3 lines of setae, T2-5 setulose. S5 1.3x as long as wide, 1.4x as long and 1.0x as wide as S4, roughly rectangular, posterior margin indented, posterior 2/3 setulose. Male genitalia with 1 seta on subepandrial plate, surstylus 1.3x as long as epandrium high, bent posteriorly and tip slightly bent anteriorly, dilated apically (1.1-1.2x), 6.4-6.5x as long as wide, structure of lateral surface smooth, medial surface without setulae.
Special characters: mesonotal setulae scarce, setae on lunule longer than interfrontal setulae.
Body length: 2.3 mm; wing length: 2.2-2.4 mm.