Scirtothrips australiae Hood

Scirtothrips australiae Hood

[Figs 4, 25, 40, 51]

Scirtothrips australiae Hood, 1918: 75

Glaucothrips auricorpus Girault, 1927: 1. syn. n.

Both Hood and Girault based their species on single females. The Hood specimen was restudied and illustrated by Palmer & Mound (1983), but the species remained known only from this single female. Subsequently, the Girault species was recognised as a member of Scirtothrips by Mound & Houston (1987), but was not compared to any other member of the genus. The original, and totally inadequate, description by Girault was: “Orange, antennae pale, dark from middle of 4, wings brown, upper vein 12, lower, 5 setae. Inner posteriolateral a bristle, outer a seta. Female, Beerwah, forest, Oct.” Both holotypes have now been re­examined, that of Hood loaned from the U.S. National Museum of Natural History, Washington D.C., and that of Girault from the Queensland Museum, Brisbane. Both are uncleared, and the Hood specimen has lost much of its colour presumably due to prolonged storage in alcohol. However, sufficient details are available on both specimens to consider that they represent the same species, particularly in the light of the variation observed in recently collected material, and recorded in the redescription below. The forewings of the two holotypes represent the extremes of variation in this species; the Hood specimen has only one seta on the second vein, and all the posteromarginal cilia are straight apart from two near the base that are undulating; the Girault specimen has five setae on the second vein, and many of the posteromarginal cilia are undulating. However, variation between these extremes has been observed amongst individuals from populations around Canberra, where this thrips breeds on the leaves of Kunzea ericoides (sometimes identified as Leptospermum sp.) [Myrtaceae]. A few adults have been taken from the immature leaves of one unidentified Eucalyptus sapling [Myrtaceae], and a sample of both sexes was taken from Exocarpos cupressiformis [Santalaceae] at Nelligen near Bateman’s Bay. S. australiae will probably prove to be widespread in eastern Australia; one female has been studied from the SW National Park of Tasmania, and another from Melaleuca leucadendra at Townsville, Queensland. The holotype came from Pentland, near Charters Towers, and the Girault holotype from just north of Brisbane. In contrast, a single female from New Caledonia recorded as S. australiae by Bournier & Mound (2000) has the pronotal striae much wider apart than in specimens from Australia, and probably represents a further undescribed species.

Female macroptera. Colour: Yellow, tergites with pale brown markings medially, also ocellar region; antecostal ridges on tergites III­VIII dark across full width of segments, on sternites III­VII shaded full width of segments; sternites III­VII with weak shading; forewings weakly shaded, paler toward apex; antennal segment 1 pale, II­VIII dark with bases of segments III­IV pale.

Structure: Vertex closely striate, ocellar region with weak reticulate sculpturing; ocellar setae pair III usually closer together than their length, arising just anterior to tangent between anterior margins of posterior ocelli; two pairs of post­ocular setae at least as long as ocellar setae pair III, p.o. S1 almost twice as long as length of a posterior ocellus. Pronotum with anastomosing transverse striae closely spaced; 4 anteromarginal setae, 10­ 14 discal setae; 4 pairs of posteromarginal setae, S2 about 50 microns long, two to three times as long as S1, S1 subequal to S3 and both longer than S4. Metanotum transversely reticulate anteriorly, longitudinally reticulate posteriorly; median setae close to anterior margin. Forewing scale with 4 marginal setae; first vein setae 1­7+1­3+1­2+0­1+0­1; second vein 1­5 setae; proximal posteromarginal fringe cilia wavy. Tergites III­V with median setae arising in­line with discal setae, relatively small and separated by at least 2.5 times their length; tergal microtrichial fields with 3 discal setae; VIII with few discal microtrichia medially, posteromarginal comb complete; IX with discal microtrichia on posterior half weakly developed. Sternites III­VI with 3 pairs of posteromarginal setae arising at margin; microtrichia extending just mesad of S2.

Male macroptera. Similar in colour and sculpture to female but smaller; tergite IX with pair of short dark drepanae; aedeagus apparently without spines.