Female either fully winged or micropterous. Body bicoloured with abdomen brown but head and pronotum with brownish-yellow areas; legs largely yellow with femora shaded; major setae pale; antennal segment II dark, I and III–IV almost yellow, V with apex light brown, VI–VII brown; fore wings pale. Antennae 7-segmented; III–IV each with short forked sense cone. Head with 2 pairs of ocellar setae; pair III no longer than distance between 2 ocelli, arising just outside ocellar triangle; postocular setae pairs I–III about as long as ocellar setae III. Pronotum with 2 pairs of posteroangular setae; posterior margin with 3 pairs of setae; discal area almost without sculptured striae, posterior third with one pair of setae medially. Mesonotum with paired anterior campaniform sensilla; median setae arise well in front of posterior margin. Metanotum with irregular reticulation medially; median setae long, arising near middle of sclerite; campaniform sensilla absent. Fore wing first vein with 3 setae on distal half; second vein with about 12 setae. Abdominal tergite II with 4 lateral marginal setae; tergites V–VIII with paired ctenidia, on VIII posteromesad to spiracles; III–VI each with transverse row of 3 pairs of equally long discal setae; tergite VIII posteromarginal comb absent medially, with a few triangular teeth laterally, discal setae S1 equal in size to S2; pleurotergites with no discal setae, sculpture lines with weakly dentate microtrichia, posterior margin with dentate microtrichia; tergite IX with 2 pairs of campaniform sensilla, X with median split. Sternites with no discal setae; sternite I with 2–3 very small setae at anterior margin; sternite VII marginal setae S1 arise close to margin.
Male micropterous, light brown to yellow, smaller than female; tergite VIII with no posteromarginal comb; tergite IX median setae slender, transverse row of 4 setae posterior to campaniform sensilla; sternites III–VII each with transversely oval pore plate.
The genus Thrips is the second largest genus in the Thysanoptera, and currently includes, worldwide, over 290 species. All members of genus Thrips lack ocellar setae I on the head, and they all have ctenidia on tergite VIII posteromesad to the spiracles. Other characters, such as number of antennal segments, number of setae on the fore wing veins, and number of discal setae on the sternites are variable between species (Palmer, 1992; Nakahara, 1994; Mound & Masumoto, 2005). Thrips discolor is one of the few species of the genus Thrips that commonly produces short-winged adults. Even the fully-winged individuals have the metanotum more transverse than is typical of macropterae, and the tergites bear three pairs of unusually long discal setae.
Feeding and breeding on the leaves of its host plants, and apparently specific to Ranunculus repens [Ranunculaceae].
Locally common in Britain from Kent to northern Scotland, and also recorded from Northern Ireland as well as the Republic of Ireland (Morison, 1971; Mound et al., 1976; O'Connor, 2008). This species is widespread across northern and eastern Europe, and is also found in North America (Nakahara, 1994).
THRIPIDAE - THRIPINAE
Thrips discolor Haliday
Thrips discolor Haliday, 1836: 449
Thrips pallens Haliday, 1836: 450
Thrips nubilans Hood, 1941: 148
Morison GD (1971) Observations and records for some British Thysanoptera. XV Thripidae, Thrips discolor Haliday. The Entomologist 104: 276–281.
Mound LA & Masumoto M (2005) The genus Thrips (Thysanoptera, Thripidae) in Australia, New Caledonia and New Zealand. Zootaxa 1020: 1–64.
Mound LA, Morison GD, Pitkin BR & Palmer JM (1976) Thysanoptera. Handbooks for the Identification of British Insects 1 (11): 1–79.
Nakahara S (1994) The genus Thrips Linnaeus (Thysanoptera: Thripidae) of the New World. United States Department of Agriculture. Technical Bulletin 1822: 1–183.
O’Connor JP (2008) A review of the Irish thrips (Thysanoptera). Irish Naturalists’ Journal 29: 20–24.
Palmer JM (1992) Thrips (Thysanoptera) from Pakistan to the Pacific: a review. Bulletin of the British Museum (Natural History) Entomology Series 61 (1): 1–76.