Female macropterous; body color mainly dark brown, tube slightly paler basally; legs dark brown, apex of femora and fore tarsi yellow, tibiae paler basally and apically, fore tibiae slightly paler than the others; antennomere II brown with yellowish apex, III brown with yellow pedicel, remaining antennal segments dark brown; wings brown with darker base. Antennae 8-segmented, antennomere IV with 3 sense cones. Head slightly longer than wide, constricted basally; postocellar setae short. Pronotum with 5 pairs of well-developed setae, anteromarginal pair very short, anteroangular and midlateral pairs somewhat elongate, epimeral and posteroangular pairs are the longest. Metanotum with a pair of stout median setae. Metathoracic sternopleural sutures present. Abdominal tergites II–VII with 1 pair of wing-retaining setae. Tube cylinder-shaped to weakly constricted medially, constrict apically, about 2.3x as long as basal width, without lateral setae. All legs similar in appearance, fore tarsi without a tooth. Fore wings without duplicated cilia.
Male macropterous. Mesothorax with projections anterolaterally. Pore plates absent.
Intraspecific variation
Unknown.
Genus and similar species information
Gastrothrips is a genus with almost 40 species and widely distributed in the tropical regions of the world, but especially in the Neotropics. There is a lot of morphological diversity within this group, and it is possible that some forms represent distinct evolutive lines. Gastrothrips species are distinguished from other Brazilian Idolothripinae by having only three short sense cones on antennomere IV, while the rest of the subfamily usually has 4 sense cones in this antennal segment. Moreover, Gastrothrips species have metathoracic sternopleural sutures, pelta usually triangular and with basal wings, and the tube is relatively short, usually constrict apically. Gastrothrips fumipennis is the only species of Gastrothrips in Brazil that does not have duplicated cilia on the forewings; it is considered to be closely related to G. abditus, from which is differentiated by the generally darker color, and absence of curved setae basally on fore femora in males. A key to some species of Gastrothrips (including the ones recorded in Brazil) is available in Mound (1974).
