Pipizella certa Violovitsh, 1981

Figs 3, 4A, 7, 11A, 12A

Material examined (females only)

FINLAND • 1 ♀; Lohja, Vainiola; 6680:3328 [60°12′ N, 23°55′ E]; 16 Jun. 2004; A. Haarto leg.; A. Haarto det.; AHa24-001288, Coll. ZMUT, DIPT_01239 • 1 ♀; Laukaa, sorakuoppa; 69207:34333, [62°23.1’′N, 25°43.2′ E]; 17 Jul. 2006; Iiro Kakko leg.; det. A. Haarto; AHa24-001311, Coll. IKC • 1 ♀ Joutseno, Riikanmaa; 67765:35913 [61°05.3′ N, 28°41.4′ E]; 28 Jun. 2023; A. Haarto leg.; AHa23- 000414, Coll. AHC.

Description of female

General appearance as in Fig. 3. Body length 7.34–7.75 mm (mean 7.48 mm) and wing length 4.64– 4.89 mm (mean 4.74 mm) by three measured specimens.

HEAD. Shiny black. Eyes 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 dorsally 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 small prominent mouth edge. Face with white semierect hairs. Height of gena is about a third of the length of its white erect hairs. Frontal ratio DBE/DBO is 1.61–1.94 (mean 1.72). The width of frons (DBE) and the distance between outsides of the hind ocelli (DBO) are measured at level of the posterior ocelli (see Fig. 2). Frons mainly with white erect hairs, but anteriorly near lunule and in 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 1.96–2.26 (mean 2.09) times as long as its maximum width. Arista bare, apically brownish black and yellowish brown on basal ⅓ and about as long as basoflagellomere.

THORAX. Scutum and scutellum shiny black with short, pale yellow erect hairs. Posterior margin of scutellum dorsally with pale yellow erect hairs almost as long as length of scutellum and ventrally with short white hairs. Pleura 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 long 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 hyaline. Pterostigma yellowish brown.

LEGS. Coxae dull black with grey pollinosity. Front and mid coxae with adpressed short white hairs. Hind coxa with erect white hairs. Trochanters black, front and mid trochanters 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 hairs about as long as diameter of femur. Hind femur mainly with erect pale yellow hairs somewhat longer than the diameter of the femur. Tibiae black, but apically narrowly yellow, and basally the length of the 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 1.4 times as long as diameter of tibia. Basotarsomere of front and mid tarsi yellow. Hind tarsus with basotarsomere dorsally brown and ventrally yellow. Otherwise, tarsi brown, but 2 nd tarsomere of mid tarsus sometimes yellow. All tarsi with adpressed pale yellow 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 2–4 at least twice as wide as wide as long. Ratio T4WL is 1.31–1.45 (mean 1.38) measured as in Fig. 1. Sterna shiny brown, but sternum 1 dull black with grey pollinosity. Sternum 2 with long white erect hairs. Sternum 3 with semi-erect white hairs anteriorly and adpressed white hairs posteriorly. Sternum 4 with erect white hairs anteriorly and adpressed white hairs posteriorly. Sternum 5 with some black erect hairs.

Differential diagnosis

Both sexes of Pipizella certa can be readily differentiated from the two other Finnish species based on the entirely yellow front basotarsomere, and in the males also by the structure of the male genitalia. The female of Pipizella certa has on average a narrower frons and a shorter basoflagellomere than either P. obscura or P. viduata (Fig. 4); however, the number of studied specimens is small.

Distribution.

Estonia, Finland (Fig. 14A), Russia, Sweden.