Scirtothrips albomaculatus Bianchi

[Figs 2, 39, 55]

Scirtothrips albomaculatus Bianchi, 1945: 263 ­266.

Described from a single female taken on a rose flower in Noumea, New Caledonia, this species was redescribed by Palmer & Mound (1983) from a few specimens taken widely across New South Wales and South Australia. Only once has it been found breeding in large numbers, and this was on Dodonaea viscosa leaves [ Sapindaceae] at several sites on Lord Howe Island (Mound, 1998). However, has been collected at Mundubbera in Queensland in association with minor damage to citrus fruits. S. albomaculatus has been taken rarely from any Acacia species, but it is a member of an Australian species­group in which at least two species, S. eremicus and S. pilbara (probably also S. astibos), are associated with Acacia species. Both Acacia and Dodonaea are widespread across Australia, and this may account for the wide distribution of the thrips species. Members of the S. albomaculatus species group have three (not two) pairs of setae in the postocular row, five (not four) pairs of pronotal posteromarginal setae, and the males lack drepanae on the ninth tergite. Within this species­group, indeed within the genus, S. albomaculatus is particularly unusual in that the marginal setae of the median sternites arise well in front of the posterior margin.

Female macroptera. Colour: Yellow, rarely with brown marking medially on tergites, antecostal ridges brown on tergites III – VIII and sternites IV – VII; forewings pale; antennal segments I – III pale, IV – VIII darker.

Structure: Head about twice as wide as long, postocular and ocellar region closely striate; ocellar setae pair III arise near margins of ocellar triangle; compound eyes with no ommatidia strongly pigmented; three pairs of post­ocellar setae longer than ocellar setae pair III. Pronotum closely striate, with 4 ­ 6 anterior marginal setae, 8 ­ 12 discal setae; 5 pairs of posteromarginal setae, S2 clearly longer than S1. Metanotal sculpture transverse anteriorly, longitudinally reticulate posteriorly; median pair of setae at anterior margin. Forewing scale with 4­5 marginal setae; second vein with 3 – 8 setae; posteromarginal fringe cilia all straight. Tergite I with no discal setae, III­V with bases of median setae close together; tergal microtrichial fields with 3 discal setae; VIII with discal microtrichia present anteromedially, posteromarginal comb complete; tergite IX with discal microtrichia present on posterior half. Sternites with microtrichia extending just mesad of S2; marginal setae arising in front of posterior margin.

Male macroptera. Similar to female in colour and sculpture, but smaller; tergite IX without drepanae; aedeagus without paired arrays of spines, but apex with series of small spines.