Pipizella obscura van Steenis & Lucas, 2011

Figs 1–2, 4B, 5, 6A, 8–9, 11B, 12B

Material examined (females only)

FINLAND • 1 ♀; Suomussalmi, Lehtovaara; 72388:36243 [65°13.3′ N, 29°39.2′ E]; 29 Jun. 2011; A. Haarto leg.; AHa11-003676; DNA MZH_HP.585 [specimen considered lost] • 1 ♀; Kuusamo, Juuma; 73543:36056 [66°15.8′ N, 29°20.8′ E]; 26 Jun.2019; A. Haarto leg.; AHa19-000709; FinBOL DNA, JP2022-010, TACHF158-22; Coll. AHC • 1 ♀; Hämeenlinna, Hattelmalanharju; 6766:3362 [60°58′ N, 24°26′ E]; 24 May 2010; Iiro Kakko leg.; AHa24-001297; Coll. IKC • 1 ♀; Riihimäki, Monni; 67311:33819 [60°40.3′ N, 24°50.1′ E]; 20 Jul.2014; Iiro Kakko leg.; AHa24-001298; Coll. IKC • 1 (Collected with a male (AHa24-001308, Coll. IKC)) ♀; Janakkala, Suurisuo; 67663:33816 [60°59.3′ N; 24°48.5′ E]; 4 Jun. 2018; Iiro Kakko leg.; AHa24-001299; Coll. IKC • 1 ♀; Hämeenlinna, Hattelmalanharju; 67651:33632 [60°58.3′ N; 24°28.2′ E]; 12 Jun. 2021; Iiro Kakko leg.; AHa24-001300; Coll. IKC • 1 ♀; Luumäki; 67553:35174 [60°54.4′ N, 27°19.0′ E]; 16 Jun. 2022; Iiro Kakko leg.; AHa24- 001301; Coll. IKC • 1 ♀; Imatra, Mellonmäki; 67848:35942 [61°09.6′ N; 28°44.8′ E]; 30 Jun. 2023; Iiro Kakko leg.; AHa24-001302; Coll. IKC • 1 ♀; Lappeenranta, Rantatie X; 67832:35838 [61°08.9′ N; 28°33.1′ E]; 28 Jun. 2023; Iiro Kakko leg.; AHa24-001303; Coll. IKC • 1 ♀; Liperi, Ylämylly, ratapiha; 69489:36320 [62°37.2′ N; 29°34.1′ E]; 9 Jul. 2018; Iiro Kakko leg.; AHa24-001305; Coll. IKC • 1 ♀; Kitee, Partasensaari; 68863:36702 [62°02.7′ N; 30°15.2′ E]; 10 Jul. 2018; Iiro Kakko leg.; AHa24- 001306; Coll. IKC • 1 ♀; Sodankylä, Madevaara S; 74547:34836 [67°10.8′ N; 26°36.7′ E]; 24 Jun. 2018 Iiro Kakko leg.; AHa24-001307; Coll. IKC.

Description of female

General appearance as in Fig. 5. Body length 5.32–7.36 mm (mean 6.28 mm) and wing length 3.64– 4.82 mm (mean 4.19) (n = 11).

HEAD. Shiny black. Eye with short white hairs. Width of ocellar triangle is 1.3 times its length. Ocellar triangle with pale yellow erect hairs. Vertex over three times as broad as the diameter of an ocellus and with pale yellow erect hairs. Occiput laterally narrower than the diameter of an ocellus and with white short erect hairs. Face flat without facial tubercle and with a weakly prominent mouth edge. Face with white semi-erect hairs. Height of gena is about a third of the length of its white erect hairs. The frontal ratio DBE/DBO is 1.85–2.08 (mean 1.96). Frons mainly with white erect hairs but anteriorly near lunule and at most the posterior third in front of ocelli with black erect hairs. Lunule shiny black. Antennal fossa not separated by a medial extension of the lunule. Antenna brownish black. Maximum length of basoflagellomere 2.05–2.55 (mean 2.25) times as long as its maximum width. Arista bare, apically brownish black and yellowish brown in basal ⅓, about as long as basoflagellomere.

THORAX. Scutum and scutellum shiny black with short, pale yellow erect pilosity. Posterior margin of scutellum dorsally with pale yellow erect hairs as long as half the length of scutellum, and ventrally with short white hairs. Pleuron dull black, mainly with grey pollinosity, anepimeron and katepisternum partly shiny and anepisternum anteriorly shiny and posteriorly pollinose. Posterior part of anepisternum and anterior part of anepimeron with pale yellow erect hairs. Dorsal part and ventral corner of katepisternum with white erect hairs. Calypter white with pale yellow margin and white hairs on margin. Halter pale yellow with pale brown base of stem.

WING. Completely microtrichose. Membrane with a slightly brownish tinge. Pterostigma yellowish brown.

LEGS. Coxa dull black with grey pollinosity. Front and mid coxa with adpressed short white hairs. Hind coxa with erect white hairs. Trochanters black, front and mid trochanter dull with grey pollinosity and hind trochanter shiny. Femora mainly black but apically narrowly yellow. Front and mid femur mainly with semi-erect short pale yellow hairs but posteriorly with pale yellow and apically some black erect hairs about as long as diameter of femur. Hind femur mainly with erect pale yellow hairs somewhat longer than diameter of femur. Tibiae black but apically narrowly yellow and basally length of yellow part varies from a third to half of tibial length. Tibiae with semi-erect white hairs sometimes mixed with some black hairs. Longest hairs on anterior side of hind tibia are about 1.3 times the diameter of the tibia. Basotarsomere of front tarsus dorsally brown and ventrally brownish yellow. Basotarsomere of mid tarsus yellow. Otherwise, front and mid tarsi brown. Hind tarsus dark brown with a long thickened basotarsomere. All tarsi with adpressed pale yellow hairs sometimes mixed with some black hairs.

ABDOMEN. Terga shiny black, with predominantly short white erect hairs, interspersed with various amounts of black hairs. Posterior margins of terga 2–3 broadly with short black erect hairs. Anterior margins of terga 3–4 broadly with short black erect hairs. Anterior corner of tergum 2 laterally with some long white hairs. Terga 2–3 at least twice as wide as long, and tergum 4 often somewhat less than twice as wide as long. Ratio T4WL is 1.03–1.17 (mean 1.14) (measured as in Fig. 1). Sterna shiny brown, but sternum 1 dull black with grey pollinosity. Sternum 2 with long white erect hairs. Sterna 3–5 with white erect hairs, but adpressed on posterior half of sternum 4.

Differential diagnosis

The female of P. viduata is on average slightly longer (mean 6.78 mm) than that of P. obscura (Supp. file 2). The longest hairs on the anterior side of the hind tibia are about 1.4 times as long as the diameter of tibia, whereas in P. obscura this ratio is about 1.3.

The distinct difference between females of Pipizella obscura and P. viduata is the shape of tergum 4. In Pipizella viduata tergum 4 is short and its width at the posterior margin is broad, whereas in P. obscura tergum 4 is long and its width at the posterior margin is narrow (Fig. 6). Thus, the ratio T4WL is not overlapping between these species. The mean of the ratio T4WL is 1.41 (range 1.33–1.54) in P. viduata and 1.14 (range 1.03–1.17) in P. obscura (Supp. file 2). Almost all P. viduata specimens could be separated from P. obscura using the shape of tergum 4. The males of these species can be identified by the characteristic features of the male genitalia. Pipizella obscura has a narrow, basally broadest, inner median flange of the hypandrium, whereas the inner median flange is broad (with broadest point medially) in P. viduata. The post-anal hood is apically almost straight in P. obscura (Figs 8C and 9C), whereas it is apically rounded in P. viduata (Fig. 10C).

Distribution.

Finland (Fig. 14B), Sweden.