Calosoma (Calosoma) frigidum Kirby, 1873

Length 19-27 mm. It is a neo Arctic vicariant of C. inquisitor of which is very similar. As in C. inquisitor the lateral margin of the pronotum is missing in the whole fourth posterior part, but compared to C. inquisitor, C. frigidum is well charecterized by the less transverse pronotum with the rear as wide as the front and with rounded sides. The color of the upper body is dark with bronze or greenish lustre and with coppery metallic foveae on the primary intervals of the elytron. The tarsi of the male forelegs show four dilated segments having setal pads as happens with C. inquisitor inquisitor but in case of C. frigidum the aedeagus is thinner and slightly bent at the apex. For this single species, Breuning (1927), had created the subgenus Syncalosoma.
C. frigidum is relatively more common in southern Canada, where it slightly exceeds the latitude of 58 degrees north that possibly is the northernmost latitude reached by a Calosoma, and it is found in the United States from the Atlantic coast, becoming rarer up to the edge of the Rocky Mountains.

Examined specimens and literature’s data
Canada. Alberta: Athabasca, Keg River, Chauvin (www.inaturalist.org/), Dixonville, Edmonton, Ministik Lake, Leduc (UASM), Spirit Rocks Nature Sanctuary (www.gbif.org), Fort McMurray (Lindroth, 1961: 47); British Columbia: Fisher Creek (UASM), Terrace (Lindroth, 1961: 47), Stone Mountain Park (www.inaturalist.org); Manitoba: Winnipeg, (SB), Carberry (TL), Birds Hill Provincial Park (www.inaturalist.org/); New Brunswick (Lindroth, 1961: 47), Brandon (www.inaturalist.org); Nova Scotia: Kejimkujik National Park (www.gbif.org), Baddeck, Cape Breton Island (Lindroth, 1961: 47), Cumberland County (www.inaturalist.org/); Ontario: Kitchener (SB), Cawagan lake (SB), Algonquin Park (Crins, 1980), Macdiarmid, Lake Nipigon, Favourable Lake (Lindroth, 1961: 47), Prince Edward county (UASM), St. Joseph Island, Thunder Bay District (www.inaturalist.org/); Prince Edward Island (Bosquet, 2012: 230); Quebec: Quebec Aéroport, Sainte-Hedwidge, La Haute-Côte-Nord, Clarendon, Cap du Bon Desir (www.inaturalist.org/), Lévis (SB), Berthier (UASM), Gatineau Park (www.gbif.org), Ile de Montreal (SB), Lake Duparquel (Lindroth, 1961: 47), Mont-Laurier (SB); Saskatchewan: Cypress Hills (UASM), Prince Albert (www.gbif.org), Craven (Lindroth, 1961: 47), Meadow Lake Provincial Park, Lac des Iles (www.inaturalist.org)
United States. Alabama: Huntsville (www.inaturalist.org); Colorado: Routt County (Steamboat Springs), Larimer County, La Plata County (www.inaturalist.org); Connecticut (Burgess & Collins, 1917: 44); Georgia (Burgess & Collins, 1917: 44): Lumpkin County, Appalachian Trail, Stephens County (www.inaturalist.org); Illinois: Cook co , Chicago (UASM); Indiana (holotype of frigidum levettei, NMNH); Iowa (Burgess & Collins, 1917: 44); Louisiana (Bosquet, 2012: 230); Maine: Oxford co , Paris (UASM), Franklin co (http://bugguide.net/), Mount Desert Island, Sebascodegan Island, Waldo co., Hancock co. (www.inaturalist.org/); Maryland: Allegany co , Rawlings (EM); Massachusetts: Essex co , Saugus (UASM), Boston (Burgess & Collins, 1917: 45), Suffolk co (http://madrean.org/), Wellesley, Sandwich (Burgess & Collins, 1917: 45), Berkshire County (www.inaturalist.org); Michigan: Ontonagon County, Montmorency County, Ogemaw County (www.inaturalist.org); Minnesota: Becker County, St. Louis County (www.inaturalist.org/), Wabasha County (http://bugguide.net/); Missouri (Bosquet, 2012: 230); Nebraska (Burgess & Collins, 1917: 44); Nevada: Quaking Aspens (La Rivers, 1946: 135); New Hampshire: Tamworth, North Conway (Burgess & Collins, 1917: 45); New Jersey: Cape May co. (www.gbif.org), Sussex co., Sparta (UASM); New Mexico: Cibola co. (http://bugguide.net/), San Miguel County (www.inaturalist.org); New York: Geneva, Gates, Seneca Castle (Burgess & Collins, 1917: 45), Willard, (EM), Tompkins co., Ithaca (UASM); North Carolina (Bosquet, 2012: 230): Pisgah National Forest (www.inaturalist.org); North Dakota (Bosquet, 2012: 230); Ohio: Lucas co., Oak Openings Park (SB), Franklin co. (www.gbif.org); Oklahoma (Bosquet, 2012: 230); Pennsylvania: Allegheny co., Aspinwall (UASM); Rhode Island; South Dakota; Tennessee (Bosquet, 2012: 230); Texas: Galveston (Bousquet, 2012: 230); Utah: Salt Lake co. (www.gbif.org), Iron co. (http://bugguide.net/), Provo cañon, Timpanogoa (La Rivers, 1946: 135); Vermont: Windham co., Dummerston (UASM), Washington County, Addison County (www.inaturalist.org/); Virginia: Giles County, Shenandoah National Park (www.inaturalist.org/); West Virginia: Morgan co. (http://bugguide.net/); Wisconsin: Ashland co. (http://bugguide.net/), Bayfield County (www.inaturalist.org); Wyoming: Albany county (www.inaturalist.org).

Notes: Diurnal and nocturnal, winged, attracted to light at night. This species may live in all kinds of habitats, but apparently prefers open woodland, both coniferous and decidous forests. Adults easily climb trees, and shelter in leaf litter. Adults and larvae of this species has been noted as predaceous on caterpillars and pupae of Heterocampa guttivitta Walker, L. Choristoneura murinana Hübner, Operophtera brumata Hulst and Lymantria dispar. As it happens with C. inquisitor of which C. frigidum could be considered vicariant, significant population rises may occur concurrently with large populations of caterpillars they prey upon. A high degree of flight activity was observed within areas of high beetle density, including some mass flights possibly also influenced by meteorological factors (Crins, 1980).
The adult individuals of this species are active in spring and summer from April up to July (Burgess & Collins 1917: 53) up to August (Snider & Snider, 1997) or to November according to Erwin (2007: 93). It is still probable that this quote refers to specimens found overwintering, in their own pupal cavity in the soil (Larochelle and Larivière, 2003: 178).
Larval stages have been described by Burgess (1896: 419) and later by Lapouge (1908: 163).
C. frigidum has been imported from the United States in Hawaii as possible help in controlling the infestations of Lepidoptera Noctuidae, and although later it has been cited as part of the entomological fauna of the Islands (http://www2.bishopmuseum.org /HBS/checklist), acclimatization failed (Liebherr et al., 2023).

Calosoma (Calosoma) frigidum ♂ Kirby, 1873 Canada, Manitoba, Winnipeg, King's park, 23.VI.08, Lawton lgt.

Calosoma (Calosoma) frigidum ♀ Kirby, 1873 Canada, Quebec, Lévis, 15.VI.74