Both sexes fully winged. Body yellow, antecostal ridges on tergites and sternites dark; fore wings shaded near base but pale distally; antennal segment I pale, II–VIII darker. Antennae 8-segmented, III and IV each with forked sense cone. Head with vertex closely striate, ocellar region with several transverse lines; ocellar setae pair III about twice as long as diameter of one posterior ocellus, close together between midpoints of posterior ocelli; two pairs of post-ocular setae. Pronotum with transverse striae not closely spaced, distance between lines about equal to diameter of a discal setal pore; posteromarginal setae S2 50–65 microns long, length more than twice diameter of antennal segment II. Metanotal reticulation almost equiangular on posterior half; median setae close to anterior margin. Fore wing clavus with 4 marginal setae; first vein setae with about 10 setae; second vein with 2–3 setae; all posteromarginal fringe cilia straight. Tergite I without long discal setae, III–V with median setae longer than distance between bases; tergal microtrichial fields with 4–6 discal setae; VIII with discal microtrichia anteromedially, posteromarginal comb complete; IX without discal microtrichia. Sternites III–VI with microtrichial fields extending just mesad of setae S2.
Male similar to female but smaller; without drepanae on tergite IX.
The genus Scirtothrips comprises over 100 described species worldwide, mostly in warmer countries. These species resemble species of Neohydatothrips in having the lateral thirds of the abdominal tergites covered in closely spaced rows of fine microtrichia, but the most closely similar genus is Drepanothrips. S. inermis is similar to dorsalis in having the fore wing cilia straight, and tergite VIII with discal microtrichia, but the sternites lack microtrichia medially, and the pronotal posteroangular setae are much longer.
Feeding and breeding on leaves, and recorded from a wide range of shrubs and trees.
Discovered breeding outdoors on Laurus nobilis in Central London in 2000 (Collins, 2006) and subsequently found under glass at the Royal Botanic Gardens, Kew, and at a commercial nursery, the latter also on L. nobilis (Collins, 2010a). Known mainly from western Mediterranean countries and the Atlantic islands, this species has also been found in southern Australia where it is common on Norfolk Island (Mound & Wells, 2015), New Zealand, Cape Verde Islands and California (Mound & Stiller, 2011).
THRIPIDAE - THRIPINAE
Scirtothrips inermis Priesner
Scirtothrips inermis Priesner, 1933: 186
Collins DW (2006) Odontothrips confusus Priesner (Thysanoptera: Thripidae) new to Britain and recent records of other British thrips. British Journal of Entomology and Natural History 19: 145–156.
Collins DW (2010a) Thysanoptera of Great Britain: a revised and updated checklist. Zootaxa 2412: 21–41.
Mound LA & Stiller M (2011) Species of the genus Scirtothrips from Africa (Thysanoptera, Thripidae). Zootaxa 2786: 51–61.
Mound LA & Wells A (2015) Endemics and adventives: Thysanoptera (Insecta) biodiversity of Norfolk, a tiny Pacific Island. Zootaxa 3964: 183–210.