Pegomya grahami Michelsen & Ackland, sp. nov.

4. Pegomya grahami Michelsen & Ackland, sp. nov.

Figs. 19–23.

‘ Pegomya maculata Stein’; Griffiths 1984: 305, figs. 426–429; Ackland & Merz 2003: 210. Misidentifications.

Etymology. As a tribute to our Canadian colleague and friend, Graham C.D. Griffiths, who died from cancer on 3 May 2009, we name the present species after him. Graham had very many interests and skills in systematic biology, but among his many contributions nothing compares to his work on North American Anthomyiidae in the series ‘Flies of the Nearctic Region’ that was also initiated by Graham. From 1982 to 2004 Graham managed to publish 2635 pages with 2982 figures (mostly original drawings!) of this outstanding, nearly complete regional monograph. It is sad that he was denied the opportunity to finish off this milestone in taxonomic literature on Diptera.

Description. Male. Very similar to P. maculata but distinguished as follows: Smaller, wing length may not exceed 5.5mm. Fore femur fuscous brown with fuscous yellow tip; mid and hind femora yellow, fuscous brown on apical quarter; all tibiae fuscous yellow to yellow. Short genal setae fewer, uni-serial. Hind femur with comb of short, erect pv-setae longer, occupying basal two-thirds. Sternite V (Fig. 19) indiscernible from other species of the P. maculata species group. Hypopygium (Figs. 20, 21) different in subtle details: surstylus in lateral view broader at tip of outer apical branch and with meso-basal laminate process visible; dark-pilose basal wart, visible in posterior view, less developed than in other species. Gonites (Fig. 22) shorter; postgonite notably widened at mid-length. Phallus (Fig. 23): Posterior hump of basiphallus shallow, obtusely rounded; distiphallus convex at hind surface.

Female. Not identified.

Material examined. Type material. CANADA: Alberta: Elkwater Lake, 1 male 12.vi.1956 (E.E. Sterns) [CNC]; Kananaskis Lakes, forest W of lakes, 6000 ft., Malaise trap, 1 male 20–22.vii.1979 (A.C. Pont) [BMNH]. FINLAND: Karelia australis (Ka): Vehkalahti, 1 male 27.v.1977 (L. Tiensuu) [FMNH]. RUSSIA: Karelia russica (Kr): Kolatselga [as Kolatselkä], 4 males [one the holotype, FMNH] 13.vi.1943 (L. Tiensuu) [FMNH, ZMUC]; Paanajarvi [as Paanajärvi], 1 male (W. Hellén) [FMNH]. NORWAY: Troms (TR): Sörkjos, ‘Rikäng’ [= lush meadow], 1 male 3.vii.1956 (R. Dahl) [BMNH]. SWITZERLAND: Canton Grisons: Andeer/ Clugin, 980m, 1 male 17.vi.1994 (B. Merz) [MHNG].

Distribution. This new species is presently recorded for the first time from Canada (Alberta), Finland, Norway, Russia (Karelia) and Switzerland. The species has been recorded as ‘ Pegomya maculata ’ from Switzerland by Ackland & Merz (2003). The only record and description of ‘ P. maculata ’ from USA: Pennsylvania by Griffiths (1984) refers also to P. grahami.