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 bend 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).
Myrmica punctiventirs
Family: Myrmicinae
Myrmica Punctiventris are common in hardwood forests. They look for seeds and plant material. They live in small colonies under the bark of rotten logs, dead oak trees, leaf litter and under rocks.
Myrmica lobifrons
Myrmica sculptilis
Myrmica detritinodis
