Both sexes fully winged. Body, legs and antennae brown to dark brown, fore tarsi sometimes paler, basal 0.3 to 0.5 of antennal segment III, also apical 0.5 of segment II yellow; fore wing with three dark transverse bands, at base, medially and at apex. Antennae 9-segmented, distal segments not forming a unit, segments III–IV each with two oval or circular sensoria that protrude apically as a small cone. Head with 2 irregular rows of small setae behind eyes; compound eyes weakly prolonged ventrally but without enlarged ventral ommatidia; maxillary palps with distal segment subdivided. Pronotum posterior margin with no prominent setae. Metanotum reticulate, median setae near posterior margin. Fore tarsus with strongly recurved ventral hamus. Fore wing broad with apex rounded, cross veins prominent. Abdominal tergites with transverse lines of sculpture medially; tergite X trichobothria about as large as a setal base. Sternites III–VII with 4 pairs of marginal setae at or close to margin, supernumerary setae on VII close to margin.
Three species are known in the genus Orothrips, two from California and one from the Mediterranean region of southern Europe (Marullo & Mound, 1994). These three species are unusual amongst the Aeolothripidae in having two sensoria on the third antennal segment.
Orothrips yosemitii Moulton
The larvae, having fed in flowers in spring, drop to the soil and spin a cocoon in which to pupate (Bailey, 1949).
Adults have been collected from the flowers of many shrubs in spring, but mainly from Ceanothus flowers (Rhamnaceae)(Bailey, 1957). It is sometimes collected together with O. kelloggi.
Western North America
British Columbia, Washington, Oregon, California, Wyoming.