Polytrichothrips Priesner

Polytrichothrips Priesner, 1939: 77 . Type-species: Polytrichothrips pilosus Priesner (= Docessissophothrips laticeps Bagnall), by monotypy.

The genus Polytrichothrips was described from Sarawak, Borneo, with unique species, P. laticeps . Subsequently, Mound (2007) described additional species, P. geoffri, from Queensland, Australia. The type-species has three pairs of long cephalic setae, the postoculars, postocellars and mid-vertexals, although geoffri has only one pair of long setae, the postoculars. Therefore, a combination of three morphological features seemed to characterise this genus until now: the maxillary stylets are deeply retracted to the level of the compound eyes and close together medially; the head has a pair of ommatidium-like structures on the cheeks ventro-laterally near base; the metanotum and pelta are scarcely sculptured. However, similar maxillary stylets and ommatidium-like structures are also found in Peltariothrips and Tarassothrips, though Peltariothrips has the shorter head with the maxillary stylets somewhat wider apart from each other in the middle of head. Tarassothrips has the ommatidium-like structures situated at the middle of cheeks, and has the unusually long sense-cones on the antennal segments. Moreover, Ethirothrips tenuis has the similar elongate maxillary stylets, and E. ommatus has the similar ommatidium-like structures situated behind the middle of cheeks. As a result, the genus Polytrichothrips is hardly distinguished among the Macrothripina by the peculiar weakly sculptured metanotum and pelta, and its generic status requires re-examining.

Key to Polytrichothrips species

(*: based on the description)

1. Postocellar and mid-vertex setae elongate............................................................ laticeps *

- Postocellar and mid-vertex setae short, at least shorter than 1/3 as long as postocular setae (cf. Fig. 205)................ 2

2. Prothoracic notopleural suture complete; antennal segments I and II dark brown: head longer, more than 1.3 times as long as wide.......................................................................................... geoffri *

- Prothoracic notopleural suture incomplete (Fig. 205); antennal segments I and II brownish yellow, distinctly paler than head (Fig. 206); head shorter, about 1.1 times as long as wide …………………………………………………….. malayanus sp. n.