Phlaeothrips Haliday

Okajima, Shûji & Masumoto, Masami, 2024, The genus Hoplandrothrips and its relatives (Thysanoptera: Phlaeothripidae) from Southeast Asia and Taiwan, Zootaxa 5489 (1), pp. 22-91 : 55-56

Phlaeothrips Haliday

Phlaeothrips Haliday, 1836: 442 . Type-species: Phlaeothrips coriacea Haliday, 1836 , by subsequent designation in ICZN Opinion 865 (1969).

This genus is presumably closely related to the Holarctic genus Acanthothrips Uzel, and Mound and Marullo (1996) suggested that these two genera might be considered as a single genus. In contrast to Phlaeothrips , Acanthothrips nodicornis , the type-species of the genus, has the postocular cephalic setae closer together, the antennal segments III to VI each with an apical neck, and the fore femur with an inner sub-apical tubercle. However, some Acanthothrips species, such as A. vittatus from North America that is the type-species of the synonymous genus Notothrips Hood , has no fore femoral tubercle, and P. annamensis sp. n. described below has antennal segments III to VI each with a short apical neck. Similarly, other features, such as the length and position of postocular setae, the form and sculpture of pelta, and the length and form of posteromarginal setae (S1 and S2) on abdominal tergite IX vary between species throughout these genera. Moreover, A. nodicornis has three sense cones on antennal segment IV, whereas Phlaeothrips coriaceus , the type-species of the genus, has four sense cones on that segment. Therefore, the difference between these two genera is extremely ambiguous, and requires further study. These genera may also be related to the worldwide genus Hoplandrothrips , but usually have parallel-sided fore wings in contrast to medially weakly constricted ones. Two new species described below from northern Vietnam are compared with two European species, P. coriaceus and P. annulipes , and no character state important enough to divide the genus is found, although they have the head elongate and the posteromarginal setae on abdominal segment IX rather long. Because the postocular setae are far apart from each other and there are four sense cones on antennal segment IV, these two species are probably more closely related to Phlaeothrips than to Acanthothrips .

Diagnosis. Medium sized species, usually macropterous. Dorsal surface of body weakly or strongly reticulate. Head longer than wide, sometimes elongate; cheeks weakly rounded, with some setae that often arise on small warts or tubercles.A pair of postocular setae situated near cheeks. Eyes and ocelli well-developed.Antennae 8-segmented, segment VIII pedicellate or conical; segments III and IV truncate apically, but sometimes with short neck, with three and four sense cones respectively. Maxillary stylets usually reaching postocular setae, close together medially. Pronotal setae variable in length, usually rather short. Notopleural sutures complete. Prosternal basantra absent. Metathoracic sternopleural sutures present. Fore wings parallel-sided, with duplicated cilia. Fore femora unarmed in both sexes; fore tarsal tooth usually well-developed in both sexes. Pelta bell-shaped or trapezoidal, usually strongly reticulate. Two pairs of wing-retaining setae present on abdominal tergites II to VII (rarely II to VI); tergite IX setae S1 and S2 much shorter than tube, rarely longer than 1/2 of tube. Tube tapering, shorter than head. Abdominal sternite VIII of male with or without pore plate.