Spiriverpa albiceps (Loew)

FIGURES 6–13. Selected species documented in this paper. Fig. 6. Acrosathe vialis male, Central Saanich, British Columbia, 21 June 2021 (iNaturalist 84506944). Photo by Thomas Barbin. Fig. 7. Pallicephala pachyceras male, Lake Cowichan, British Columbia, 24 June 2020 (iNaturalist 51032384). Photo by Brian Starzomski. Fig. 8. Psilocephala vicina female, Nahatlatch Provincial Park, British Columbia, 25 June 2021 (iNaturalist 97392001). Photo by Lena Chiasson. Fig. 9. Spiriverpa albiceps female, Cape Scott, Vancouver Island, British Columbia, 28 June 2020 (iNaturalist 57752358). Photo by Thomas Barbin. Fig. 10. Spiriverpa albiceps male, Teslin, Yukon, 31 July 2020 (iNaturalist 55078839). Photo by Jukka Jantunen. Fig. 11. Tabuda planiceps female, Kilpoola Lake area, Osoyoos, British Columbia, 23 May 2022 (iNaturalist 122086201). Photo by Brian Starzomski. Fig. 12. Thereva brunnea female, Tipella, Harrison Lake, British Columbia, 6 July 2020 (iNaturalist 53228675). Photo by Blair Dudeck. Fig. 13. Thereva webbi female laying eggs in the soil. Whitehorse, Yukon, 12 July 2020 (iNaturalist 52909455). Photo by Jukka Jantunen.

FIGURES 6–13. Selected species documented in this paper. Fig. 6. Acrosathe vialis male, Central Saanich, British Columbia, 21 June 2021 (iNaturalist 84506944). Photo by Thomas Barbin. Fig. 7. Pallicephala pachyceras male, Lake Cowichan, British Columbia, 24 June 2020 (iNaturalist 51032384). Photo by Brian Starzomski. Fig. 8. Psilocephala vicina female, Nahatlatch Provincial Park, British Columbia, 25 June 2021 (iNaturalist 97392001). Photo by Lena Chiasson. Fig. 9. Spiriverpa albiceps female, Cape Scott, Vancouver Island, British Columbia, 28 June 2020 (iNaturalist 57752358). Photo by Thomas Barbin. Fig. 10. Spiriverpa albiceps male, Teslin, Yukon, 31 July 2020 (iNaturalist 55078839). Photo by Jukka Jantunen. Fig. 11. Tabuda planiceps female, Kilpoola Lake area, Osoyoos, British Columbia, 23 May 2022 (iNaturalist 122086201). Photo by Brian Starzomski. Fig. 12. Thereva brunnea female, Tipella, Harrison Lake, British Columbia, 6 July 2020 (iNaturalist 53228675). Photo by Blair Dudeck. Fig. 13. Thereva webbi female laying eggs in the soil. Whitehorse, Yukon, 12 July 2020 (iNaturalist 52909455). Photo by Jukka Jantunen.

FIGURES 14–19. Representative habitats of species documented in this paper. Fig. 14. The unglaciated British Mountains west of the Firth River, Yukon, showing steppe grasslands and arctic tundra at the northern limit of trees in Canada. Dialineura gorodkovi and Psilocephala vicina have been collected here. Photo by Sydney Cannings. Fig. 15. Sand dunes at Bennett Lake, Carcross, Yukon, habitat for a diverse therevid fauna, including Cliorismia bussi, Dialineura gorodkovi, Pallicephala occidentalis, Pandivirilia conspicua, Psilocephala vicina, Spiriverpa albiceps, Thereva foxi, and T. utahensis. Photo by Sydney Cannings. Fig. 16. Tabuda planiceps habitat at Vaseux Lake, British Columbia; Pinus ponderosa trees with Purshia tridentata (green-leaved shrub) and Artemisia tridentata (grey shrub) in foreground. Photo by Robert Cannings. Fig. 17. Mount Kobau, British Columbia; view south to Osoyoos Lake.The grassland and subalpine slopes of this locality are home to Tabuda planiceps and at least four species of Thereva: T. aurofasciata, T. cingulata, T. fucata, and T. utahensis. Photo by Robert Cannings. Fig. 18. Upper beach at Cape Cook Lagoon, Brooks Peninsula, northwestern Vancouver Island, British Columbia—the only known Canadian locality for Thereva elizabethae. Photo by Robert Cannings. Fig. 19. The lower, south-facing grassland slopes of Nares Mountain, overlooking Nares Lake, Carcross, Yukon. Home of Thereva foxi and T. webbi. Photo by Sydney Cannings.