Generic diagnosis

Small, dark brown, micropterous Phlaeothripinae. Head 1.5 times as long as wide; vertex with little or no sculpture; ocelli present but small; postocular setae long, weakly capitate; maxillary stylets slender, retracted to posterior margin of eyes, close together medially; maxillary guides stout, meeting anteriorly but without any clear bridge. Antennae 8-segmented, VIII moderately long; antennal segment III rather truncate at apex with one sense cone, IV with 3 sense cones. Pronotum with little or no sculpture; four pairs of slender, weakly capitate major setae, midlaterals not developed; notopleural sutures complete. Prosternal basantra absent; mesopresternum incomplete; metathoracic sternopleural sutures absent. Both sexes with no fore tarsal tooth. Pelta roughly triangular; tergites III‒VI each with only one pair of wing-retaining setae, arising on posterior margin; tergite IX setae S1 and S2 both finely pointed and longer than tube; tube as long as head width. Male tergite IX S2 setae short and stout; sternite VIII with no pore plate.

Relationships

Four uncleared specimens have been studied, all from Hungary, Simontornya, and all identified by Priesner. The male labelled "Type" (11.xii.1923) has, on both antennae, one sense cone on segment III and 3 sense cones on segment IV. This condition is also found on one female and one male (both 2.iii.1924). However, one female (16.i.1924) has no sense cone visible on segment III and only one visible on IV of both antennae. Sense cones in this species are exceptionally small and slender, the one on segment III scarcely 7 microns long, and those on segment IV about 10 microns long. Two specimens are mounted ventral-side uppermost, and on these the prosternal basantra are clearly absent (the Type male, 11.xii.1923 and the female 16.i.1924). Two others are mounted dorsal side uppermost, and on these an accumulation of red pigment gives the impression of basantra present (2.iii.1926) but with no evidence of an actual sclerite. Here, it is assumed that basantra are absent. The species is thus not a member of the Haplothripini, but is most probably a member of the Liothrips-lineage.

Biology

The species remain known only from a few wingless adults collected from the bark of Robinia and Salix trees. It is not possible to know if the species is fungus-feeding on woody bark, or if it is leaf-feeding and these adults were merely sheltering overwinter.

Distribution

Presumably eastern European, as it is known only from Hungary although Priesner (1964) also lists Romania. Pelikan (1965) described a subspecies, asiaticus, based on a single male from Mongolia. The description of that specimen states that there are 4 sense cones on antennal segment IV, and the S1 setae on tergite IX only 0.75 as long as the tube - character states that suggest that this subspecies is mis-associated with robiniae. There is a hand-written note by zur Strassen on a reference card at the Senckenberg Museum that suggests that asiaticus is probably a member of the genus Hoplothrips.

Nomenclature

Hadothrips Priesner, 1925: 42. Type species Haplothrips (Zygothrips) robiniae Priesner, 1924, by monotypy.

Pezidothrips Priesner, 1951: 366. Objective synonym of Hadothrips, because robiniae was designated as type species, see Bhatti (1993: 250) contrary to Priesner (1964: 174).

Only one species is recognised in this genus (ThripsWiki, 2023).

Euro-Mediterranean species
Hadothrips robiniae (Priesner, 1924).

References

Bhatti JS (1993) List of world genera of the Order Tubulifera (Insecta). Zoology 3 (2): 127–162.

Priesner H (1964) Ordnung Thysanoptera (Fransenflügler, Thripse), in Franz H, Bestimmungsbücher zur Bodenfauna Europas 2: 1–242. Akademie-Verlag.

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