Described originally as having abdominal segments II–VI sharply yellow in contrast to the brown body, this species is considered by Bailey (1951) to exist also in a form with the abdomen uniformly brown. Both sexes fully winged, or with wings no longer than width of thorax. Body color uniformly brown, or with abdominal segments II–IV, V, or VI sharply yellow; antennal segment II yellow in apical half, III yellow with apex brown; legs brown; fore wings with 2 transverse dark bands. Antennae 9-segmented, segment III with linear sensorium short, IV with sensorium less than 0.5 as long as segment and scarcely curved at apex, V–IX forming a single unit with V about equal in length to VI–IX. Head and pronotum with no long setae. Fore tarsus apically with stout recurved ventral hamus. Median marginal setae on sternites arising at or close to margin, but lateral two pairs arise sub-marginally; sternite VII with two pairs of accessory setae arising almost medially on disc.
Male without tergal tubercles; setae at base of claspers on tergite IX longer than clasper, without stout curved seta lateral to clasper.
A. auricestus often has the basal abdominal segments sharply yellow, as in A. albicinctus and A. brunneipictus that are also known in California. At least two other Aeolothrips species with the abdomen bicolored occur in western USA, A. aureus Moulton and A. bicolor Hinds, and these five species apparently all live at ground level as predators of small arthropods. However, winged females of the brown form of A. auricestus are similar in structure to those of other species in the A. fasciatus group. About 105 species are placed currently in the genus Aeolothrips. Most of these are from the Palaearctic Region (including the Mediterranean, Iran and northern India, but with five species extending through eastern Africa to South Africa), with about 30 species from the Nearctic (mainly western USA). Only one species of this genus is known from the Neotropics, A. fasciatipennis described from Chile, but Mound & Marullo (1996) indicate this is probably the same as A. fasciatus.
Commonly with reduced wings. Associated with grasses, and presumably living at ground level; presumably predatory on other small arthropods.
Western North America (British Columbia, Washington, Oregon, northern California).
Aeolothrips auricestus Treherne
Aeolothrips auricestus Treherne, 1919: 184
Mound LA & Marullo R (1996) The Thrips of Central and South America: An Introduction. Memoirs on Entomology, International 6: 1-488.