Other Common Names
Pedunculate Ground Beetle, Blue-margined Ground Beetle (P. elongatus), Fierce Ground Beetle (P. depressus)
11 spp. in 3 species-groups (all in the nominotypical subgenus) in our area, 32 spp. in 4 subgenera total(2)
Large, extra-robust, flightless ground beetles (elytra fused into rigid shell). Huge jaws, head, pronotum. Some have blue margins. Typically run about under or on leaf litter in forests.
keys to spp. in(3)(4)(5)(6)(7)
The best key to North American species of Pasimachus
is by Purrington & Drake (2005)(3)
. A common identification difficulty is sympatric Pasimachus "depressus" vs "elongatus". The dorsal habitus is much more robust/broad in "depressus", most with body length ≥ 28 mm vs ≤ 26 mm for most "elongatus". The most reliable external separator is the shape of the prosternal process (conical vs roundish) as described in the key. In "depressus", the male metatibia (distal third) bears no golden tuft of hairs, but present so in male "elongatus".
North and Middle America; in our area, most diverse in the south, with just one sp. (P. elongatus
) reaching Canada (MB-AB)(2)
caterpillars, other larval insects
Stag Beetles (Lucanidae)
(easily distinguished by their geniculate clubbed antennae)