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Myrmica
Myrmica
| 1a. | Smooth bend on antennal scape at insertion | 2 |
| 1b. | Sharp bend on antennal scape at insertion | 6 |
| 2a. | Thorax with distinct step-down between promesonotum and propodium. Propodial spines long and curved outward. Forest species | M. punctiventris |
| 2b. | Thorax without distinct step-down, but slight-to-large depression between promesonotum and propodium. Propodial spines shorter, sharp, and rearward pointing | 3 |
| 3a. | Frontal lobes flat and triangular, covering antennal insertion in plane of head when viewed in profile; ant of bogs and wet places | M. incompleta |
| 3b. | Frontal lobes upright, not covering antennal insertion and not in plane of head when viewed in profile (like horns in dorsal view) | 4 |
| 4a. | Antennae twist helically towards insertion on head (look at pattern of hairs); bog species | M. lobifrons |
| 4b. | Antennae do not twist | 5 |
| 5a. | Small cup-like surface on top of scape obscuring angle at bend; wet meadow | M. fracticornis |
| 5b. | No cuplike surface on top of scape; lower surface of long arm of scape comes up into a chisel-like ridge. Wet meadows | M. latifrons |
| 6a. | Right angle bend with large cup or ring surrounding the bend; open sandy habitats | M. americana |
| 6b. | Antennal scape with a flange at the ben | 7 |
| 7a. | Antennal scape with projection at bend, with the acute angle bend obscured by a large flange; propodial spines at 45-degree angle up (not pointing totally rearward) | M. sp. 1 ("smithana") |
| 7b. | Scape sharply bent, with pronounced flange | 8 |
| 8a. | Warm forests, light-to-medium brown, propodial spines at 45-degree angle | M. sp. 2 ("sculptilis") |
| 8b. | Boreal, dark brown-to-black, propodial spines widely spaced and directed rearward | M. detritinodis |
References:
Francoeur, A. 1997. Ants (Hymenoptera: Formicidae) of the Yukon. Pages 901-910 in H. V. Danks and J. A. Downes, editors. Insects of the Yukon. Biological survey of Canada, Ottawa, Canada.
Francoeur, A. 2006. The ant species groups Myrmica punctiventris and M. crassirugis in the Nearctic region (Hymenoptera: Formicidae: Myrmicinae). Memoirs of the American Entomological Institute (in press).
