Key to the species-groups of Formica of Manitoba
(Jeff Shaddock (unpublished) and adapted from Wheeler and Wheeler (1977))

1 a. With all the following combination of characters:  >  sanguinea Group

  - pubescence dense, at least on gaster (Fig.1a)
  - ventral border of clypeus notched in the middle
  - integument dull
  - bicoloured: head and thorax reddish brown or reddish yellow, gaster brown or black
  - metanotum small but distinctive
  - propodeum short and distinctly angulate in profile

  • Formica aserva Forel, 1901
  • Formica pergandei Emery, 1893
  • Formica puberula Emery, 1893
  • Formica rubicunda Emery, 1893
  • Formica subintegra Wheeler, 1908
  • Formica wheeleri Creighton, 1935

  • b. Without the above combination of characters   >  2

    2 a. Body slender
          Body surface shiny (Fig. 2a)
          Propodeum rounded in profile (i.e. dorum and declivity not differentiated)  >  neogagates Group

  • Formica bradleyi Wheeler, 1913
  • Formica lasioides Wheeler, 1913
  • Formica limata Wheeler, 1913
  • Formica neogagates Viereck, 1903

  • b.    Body robust
          Body surface dull (Fig. 2b)
          Propodeum angulate in profile (i.e. dorsum and declivity clearly differentiated)   >  3

    3 a.  Larger workers with posterior cephalic margin distinctly concave (Fig. 3a)
           Propodeum with dorsal and declivous faces meeting at an angle  >  exsecta Group

  • Formica exsectoides Forel, 1886
  • Formica ulkei Emery, 1893

  • b.    Larger workers with posterior cephalic margin flat or slightly convex (Fig. 3b)
           Propodeum (seen in profile) with dorsal and declivous faces evenly convex, not angulate (but still
           clearly differentiated) (i.e. dorsum and declivity clearly differentiated)   >  4

    4 a.  Erect hairs on pronotum of workers often clubbed (Fig. 4a)
           Queen never more than 5.5mm long and never larger, but is often shorter than, workers  >  microgyna Group

  • Formica spatulata Buren, 1944

  • b.    Erect hairs on pronotum of workers not clubbed (Fig. 4b)
           Queen usually more than 8mm long and noticeably larger than workers; if less than 8mm long and not
           larger than largest worker, then very smooth and shining   >  5

    5 a.  Colour: bicoloured, head and thorax reddish or yellowish red and notably lighter than gaster
           Surface mostly dull
           Frontal carinae strongly divergent dorsally (Fig. 5a)  >  rufa Group

  • Formica dakotensis Emery, 1893
  • Formica fossaceps Buren, 1942
  • Formica obscuripes Forel, 1886
  • Formica obscuriventris Mayr, 1870
  • Formica oreas Wheeler, 1903

  • b.    Colour: concolourous or bicoloured, thorax lighter than gaster and upper half of head
           Surface (especially frontal area) opaque
           Frontal carinae moderately divergent dorsally, often parallel (Fig. 5b)  >  fusca Group

  • Formica altipetens Wheeler, 1913
  • Formica argentea Wheeler, 1912
  • Formica canadensis Santschi, 1914
  • Formica fusca Linnaeus, 1758
  • Formica glacialis Wheeler, 1908
  • Formica hewitti Wheeler, 1917
  • Formica montana Wheeler, 1910
  • Formica neorufibarbis Emery, 1893
  • Formica podzolica Francoeur, 1973
  • Formica subsericea Say, 1836