Terellia (Terellia) ptilostemi ,sp. n. urn:lsid:zoobank.org:act: ABCCF42C-9FA1-4DCB-8BB3-3B2429135402 Material. Type. Holotype ♀ (pinned): Morocco, Rif mountains, Tétouan Province, Douar Chourdane, Mkhinak, 35°28.766´N / 005°19.334´E, altitude: 908 m, ex FLower heads of Ptilostemon rhiphaeus, coll. 07.07.2019, emerged 06.08.2019 (El Harym) (LESCOBIO). Paratypes: Morocco, Rif mountains, Tétouan Province, Douar Chourdane locality, Mkhinak site, 35°28.766´N / 005°19.334´E, altitude: 908 m, 1 Ơ, 1 Ơ, ex FLower heads of Ptilostemon rhiphaeus, coll. 07.07.2019, exit 06.08.2019; 1 Ơ, exit 17.08.2019; 2 Ơ, ex FLower heads of same species, coll. 15.12.2019, exit 26.04.2020; 5 Ơ, exit 27.04.2020; 1 Ơ, 1 ♀, exit 01.05.2020; 1 ♀, exit 03.05.2020; 1 Ơ, exit 04.05.2020; 2 Ơ, exit 07.05.2020; 1♀, exit 09.05.2020; 1 Ơ, 4 ♀, exit 10.05.2020; 1 Ơ, 2 ♀, exit 12.05.2020; 2 Ơ, 6 Ơ, exit 14.05. 2020; 1 Ơ, exit 17.05.2020; 1,Ơ 8 ♀, exit 21.05.2020 (El Harym); Jebel Kelti (Mountain), Aïn Akorian, altitude: 1610 m, 35°21.038´N / 005°17.198´E, 1 ♀, ex FLower heads of same species, coll. 12.01.2020, exit 26.04.2020; 2 Ơ, exit 05.05.2020; 3 Ơ, exit 07.05.2020; 3 Ơ, 1 ♀, exit 09.05.2020; 2 Ơ, 1 ♀, exit 10.05.2020; 1 Ơ, exit 12.05.2020; 2 ♀, exit 16.05.2020 (El Harym); Chefchaouen Province, Tissouka Mountain, Aïn Elma SeFLi, altitude: 1345 m, 35°09.958´N / 005°13.906´E, 1 Ơ, ex FLower heads of same species, coll. 09.02.2020, exit 01.05.2020; 2 Ơ, exit 05.05.2020; 3 Ơ, exit 07.05.2020; 8 Ơ, exit 09.05.2020; 12 Ơ, 1 ♀, exit 10.05.2020; 17 Ơ, 4 ♀, exit 12.05.2020; 3 Ơ, 7 Ơ, exit 14.05.2020; 5 Ơ, 4 Ơ, exit 16.05.2020; 13 Ơ, 20 ♀, exit 19.05.2020; Talassemtane National Park, Forest house, altitude: 1674 m, 35°08.076´N / 005°08.262´E, 1 Ơ, 04.07.2020 (net sweeping) (El Harym). D i a g n o s i s. This species can be differentiated from all other known species of Terellia by its dark brown wing pattern (fig. 1, e) of four widely connected crossbands resembling the Greek letters Π and Λ or inverted Latin letters V and U also fused along vein M 4 (= CuA 1), by the structure of the glans of the phallus (paired filaments of acrophallus, no bulged juxta at base of apicodorsal rod — figs 2, a–b) in combination with the striate patterns of the eye (fig. 1, f) and thoracic pleuron (figs 1, a–b, f–g). It is similar to the other species of the serratulae species group except in wing pattern; the other species all have entirely hyaline or slightly infuscated wings. Terellia ptilostemi appears to be most closely related to Terellia sabroskyi Freidberg which has the same host plant genus Ptilostemon, a darkened wing apex, dark bordered crossveins r-m and dm-m (= dm-cu) (pale brown in T. sabroskyi and black in T. ptilostemi), all setae (except postoculars) dark brown to black, the notopleuron and middle part of the proepisternum and anepisternum (at anterior spiracle level) brown, and oviscape moderately long (longer than tergites 4–6 combined in T. sabroskyi and slightly longer than tergites 3–6 in T. ptilostemi). D e s c r i p t i o n. H e a d pale yellowish, subshining, length: height: width ratio = 1.0: 1.0: 1.42, with FLagellomere 1, palp and proboscis yellow, ocellar triangle and arista brown to black, occiput with brown markings. Setae dark brown to black, looking paler in oblique light; postocular, postvertical and postocular setae white. Gena 0.3× as high as compound eye, brown setulose. Occiput ventrally white setulose. Palp brown setulose. Compound eye of live or freshly killed FLies greenish to red with purple horizontal band. Thorax. Mesonotum FLattened, scutum 1.3× as long as wide (measured between bases of notopleural setae), with lyrate black pattern almost reaching scuto-scutellar suture and postero-medial yellow triangle posterior to level of dorsocenral setae (fig. 1, c); dorsal part of postpronotal lobe, notopleuron and supra-alar area brown to black;ventral part of postpronotal lobe and dorsal margin of anepisternum creamy white; anepimeron and anepisternum at level of anterior spiracle brownish yellow to brown, ventral part of anepisternum and anepimeron usually yellow or with narrow creamy submedial stripe; katepisternum dorsally and meron creamy white to pale yellow, katepisternum with large triangular black spot ventromedially; postalar wall and posterior corner of anatergite black (figs 1, a–b, f–g). Scutellum FLattened, subtriangular, yellow except antero-ventral corners. Subscutellum brownish; mediotergite black, finely microtrichose laterally, with shiny patch medially. Legs yellow, with brownish tarsi, setae and setulae brown to black. Wing (figs 1, a–b, e–g) with 4 dark brown crossbands; cell bc and bases of cells bm and cua (= cup) yellowish, humeral vein bordered by brown spot; most of costal cell dark grey or brownish continuing into subbasal crossband extending from cell c across veins bm-m and section of vein CuA closing cell cua; discal band connected to subbasal band in pterostigma and cells r 1 and r 2+3 posterior of it covering crossvein r-m and extended to vein M 4 (= CuA 1) or occasionally narrowly interrupted in cell dm, connected to subapical band along vein M 4; subapical band reaching from apical part of cell r 1 across crossvein dm-m (= dm-cu) to posterior margin of wing at apex of vein M 4; widely fused to apical band in cells r 1 and r 2+3, apical band extended to apex of vein M 1. Hyaline incision between discal and subapical crossbands as wide as subapical crossband along vein R 4+5, reaching posteriorly to middle of cell dm. Halter whitish to yellowish. Abdomen (figs 1, b–c, f–g) yellow to brown, tergites 3–5(– 6 in female) each with two pairs of large subtriangular black spots at anterior margin; syntergite 1+2 usually with more or less distinct submedial pair of brown spots; tergite 5 of male with lateroapical black spots widely separated from laterobasal spots. Syntergite 1+2 entirely white setulose, tergites 3–5(– 6 in ♀) white setulose with medial areas of black setulae, these medial areas narrow in females and wider in males; tergite 5 of male mostly black setulose on posteromedial part, anterolaterally narrowly white setulose. Marginal setae on tergites 4–5(– 6 in ♀) mostly black. Tergite 5 of male 1.5 × as long as tergites 3 and 4 combined. Terminalia. Male (figs 2, a–b). Lateral surstylus with moderately long setulae, but without conspicuous marginal microtrichia. Phallus with glans very similar to that in T. serratulae (Linnaeus, 1758) with well developed basal ligula and inner dentate sclerite, narrow and moderately long paired filaments of acrophallus and moderately sclerotized apicodorsal rod without conspicuous bulged juxta at its base. Female. Oviscape (figs 1, c–d): FLattened triangular, yellow, black setulose, with black apex and pair of large triangular black anterolateral spots dorsally, sometimes fused forming entire black spot on anterior two-thirds and apex, and only brownish yellow at mid-length. Oviscape dorsally almost as long as tergites 3–6 combined and twice as long as costal cell. Eversible membrane (fig. 2, c) with moderately short taeniae and almost uniformly blunt subrectangular scales. Aculeus (fig. 2, d–e) 8.3–8.4× as long as wide, with long and narrow cercal unit: distance between ventral lobes (8th sterites) and apex 3× as long as width at level of apices of ventral lobes. Two tuberculate, conspicuously twisted spermathecae; spermathecal duct moderately long without transverse striation (fig. 2, f). Measurements [ mean, (min–max), mm]: Body length Ơ = 4.79 (4.5–5.08), wing length Ơ = 3.68 (3.46–3.9); body length ♀ = 6.22 (6.05–6.4), wing length ♀ = 4.3 (4.16–4.45), oviscape length, dorsally = 1.44 (1.33–1.56), oviscape length, ventrally (OLV) = 1.87 (1.83– 1.92), aculeus length (AL) = 1.77 (1.65–1.89); costal cell length (C2) = 0.8 (0.78–0.82); OLV/ C2 = 2.24 (2.14–2.34); AL/C2 = 2.2 (2.11–2.30). Third instar larva: length 5.74 (5.37–6.12), width 2.56 (2.5–2.62). Biology and host plants. Larvae (fig. 3) feed in the FLower heads of Ptilostemon rhiphaeus (Pau & Font Quer) Greuter (Asteraceae: Cardueae) growing in the limestone mountain ridge (fig. 2) at altitudes of 900–1800 m (fig. 4). One to three larvae were observed in each FLower head. The third instar larvae or prepupae overwinter and pupate in the FLower heads. First generation adults emerged in the laboratory from April 26 to May 20, 2020 and possibly somewhat later in nature. Adult FLies were collected by sweeping on the same plants from April to May and apparently mate and oviposit until June. Second generation larvae feed in FLower heads in July and pupate by the end of July and beginning of August. Second generation adults emerge and oviposit in August; larvae feed in August–September and then hibernate. Four endemic species of the genus Ptilostemon are known from North Africa; three are Moroccan endemics, and one is a Moroccan-Algerian endemic (Fennane et al., 1999). E t y m o l o g y. This new species is named for its host plant genus, Ptilostemon; the name is a noun in genitive case.