Both sexes fully either winged or micropterous. Body and legs brown, tarsi yellow, major setae dark brown; antennae brown, segment II darkest; fore wing pale. Antennae 7-segmented; segments III–IV each with apex slightly elongate and constricted, bearing a forked sense cone, VII short. Head wider than long; with 2 pairs of ocellar setae; pair III no longer than distance between 2 ocelli, arising just outside anterior margins of ocellar triangle; postocular setae pairs I and III equal to or slightly longer than ocellar setae III, pair II minute. Pronotum with 2 pairs of prominent posteroangular setae; posterior margin with 3 pairs of setae. Mesonotum with anterior campaniform sensilla. Metanotum transverse, with irregular reticulation medially; median setae long, arising behind anterior margin and about 0.7 as long as the sclerite; campaniform sensilla present. Fore wing first vein with 3 setae on distal half; second vein with about 10 setae. Abdominal tergite II with 3 lateral marginal setae; V–VIII with paired ctenidia, on VIII posteromesad to spiracles; tergites III–VI each with 3 pairs of equally long discal setae; VIII posterior margin with comb complete, microtrichia pale, slender, arising from triangular bases; tergite IX with anterior pair of campaniform sensilla arising anterolaterally, X conical with median split; pleurotergites without discal setae, sculpture lines and posterior margins with few or no microtrichia. Sternites without discal setae; VII with setae S1 arising in front of margin.
Male similar to female but smaller; sternites III–VII each with slender pore plate with width about 8 times as long as median length.
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). The form of antennal segments III and IV in dilatatus is rather similar to that found in Thrips klapaleki, but these two species differ in other character states, including the number of setae laterally on the second tergite, and the form of the comb on tergite VIII.
Feeding and breeding in the flowers of its host plants, and specific to various Scrophulariaceae, including species of Euphrasia, Pedicularis and Rhinanthus.
Recorded from a number of sites across England, but with most records from Scotland (Morison, 1970b; Mound et al., 1976). This species is widespread across Europe eastwards through Russia (zur Strassen, 2003).
THRIPIDAE - THRIPINAE
Thrips dilatatus Uzel
Thrips dilatatus Uzel, 1895: 202
Morison GD (1970b) Observations and records for some British Thysanoptera. XIV Thripidae, Thrips dilatatus Uzel. The Entomologist 103: 307–311.
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.
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.
zur Strassen R (2003) Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. Die Tierwelt Deutschlands 74: 1–271.