Delia bipartitoides Michelsen, sp. nov.

Delia bipartitoides Michelsen, sp. nov.

Figs. 5, 10–11.

Etymology. The specific epithet ‘ bipartitoides ’ is derived from ‘ bipartita ’, existing name for a similar species, and ‘ -oides ’, a Greek adjectival suffix meaning ‘resembling’.

Material examined. Type material. Holotype male, SWEDEN: Norrbotten: Rörbäck, Råneå, 29.vii.1978 (H. Andersson), MZLU.

Additional material (teste D.M. Ackland). RUSSIA: Yakutia [= Sakha Rep.]: Verkhoyansk, 1 male 31.vii.1969, 1 male 1.viii.1969 (Sytchevskayia), ZMMU. MONGOLIA (all Exp. Z. Kaszab 1966-8, in HNHM): Gobi Altaj aimak: Chasat Chajrehan ul, Gerbirge, c. 20km S Somon Ž argalen, 2400m, 1 male 15- 16.vii.1966. Uvs aimak: 3 km NE von Somon, Öndörchangaj, 2200m, 1 male 11.vii.1968; Pass Ulaan davaa, east slope between See Övög nuur and Ulaangom, 1950m, 2 males 6.vii.1968.

Description. This species resembles the common and widespread Delia nuda even more than the previous species, but also exhibits some notably different male sexual specializations. The following differential description will help to distinguish D. bipartitoides from D. nuda in the male sex:

Male. Fore tibia without apical pv seta vs. with a short apical pv seta. Mid femur without subapical a seta vs. with subapical a seta. Sternite III split into a pair of posteriorly diverging lobes; setation unremarkable (Fig. 5) vs. undivided; setation notably dense and upright on posterior part. Sternite IV broader than sternite V, rather densely setated on anterior part (Fig. 5) vs. normally wide, sparsely setated except at lateral margins. Surstyli slender, symmetrical, without a notch at medial margin (Figs. 10–11) vs. broader, slightly asymmetrical and distinctly notched at medial margin. Gonites and phallus similar in both species, closely resembling those of D. rimiventris (cf. Figs. 8–9).

Female. Unknown.

Distribution and biology. Evidently a very local and rare species in Fennoscandia. The type locality is a coastal site at the interior of the Bothnian Gulf. Species of Dianthus or Silene (Caryophyllaceae) are potential larval host plants in that area. Additional material from Mongolia and Russia (Yakutia) belongs to Delia bipartitoides according to D.M. Ackland, in litt.