Calosoma (Camedula) peregrinator Guérin Méneville, 1844

Length 23-33 mm. glabratum, peregrinator and sponsa are characterized by the presence of setae on the metatrochanters.
peregrinator is usually larger than glabratum and sponsa but is very variable in size, general body proportions, shape and punctuation of pronotum, presence or absence of weak striae in the elytra. But you can always easily identify it because its last abdominal segment is deeply wrinkled, in the female with erect hair.
Jeannel (1940) considered the many forms described superfluous. Among them a special case consists of the systematic position of Calosoma forreri Géhin, 1885 that correctly was considered by Breuning (1927: 103) as synonymous with C. peregrinator, but that later Jeannel (1940 : 203), followed by all subsequent authors (Gidaspow, 1959: 252 ; Erwin, 2007: 86), erroneously has attributed to C. angulicolle.
C. peregrinator is for sure a variable species. In Mexico, in particular, there are morphological variations ranging from small, very elongated specimens with almost obsolete elytral sculpture (corresponding to the characters given for Calosoma apacheana Casey, 1913), to others with strongly transverse pronotum, short and rounded elytra and punctate striae (in the old collections classified as Calosoma peregrinator amplipenne Casey, 1913).
Finally, an extreme case of morphological variation is the one of C. ampliator Bates, 1891 of which the systematic position is still under discussion. Bates (1891: 223) described the new species by comparing it with C. peregrinator that he considered the species most closely related to it. In the original description he highlighted among other characteristics: the body shape distinctly shorter and broader, the transverse pronotum with strongly rounded sides, the elytra oblong, scarcely widened behind, with finely punctate striae and visible foveae on the primary intervals.
Roeschke (1900: 62), having at the time examined the types, considered C. ampliator a synonym of C. triste (presently itself synonym of C. affine) but it must be also kept in mind that Roeschke (1900: 63) judged C. affine a simple variety of C. peregrinator. Breuning (1926b: 174), reviewing the description of Bates (1891: 223), but apparently without knowing the type, confirmed the synonymy with C. affine, followed in this by Jeannel (1940: 169). Later Gidaspow (1959: 267) reevaluated C. ampliator as a distinct species inside of the the subgenus Chrysostigma.
The Bate's and Gidaspow's descriptions as well as the result of the examination of specimens existing in various collections and classified as C. ampliator, would lead us rather to consider it a species very closely related to C. peregrinator, or better a simple morphotype of it. Bates had already stated that the two supposed species coexisted in many places in Mexico and the existence of specimens with intermediate characteristics favors the second hypothesis.
C. peregrinator (of which we think C. ampliator should be a synonym) is widespread in the south-western United States and in northern and central Mexico, approximately in an area between the 41st and 18th parallel. The area of diffusion of the species seems to exclude the subtropical zone and its presence in Panama (Chiriqui) indicated by Gidaspow (1959: 268) for C. ampliator and questioned by Erwin (1991: 28) appears unlikely.
We add that C. peregrinator was recently observed for the first time in the south of the island of Hispaniola (Dominican Republic). Taking into account the considerable distance from the known diffusion area of the species, it is probably a passive import, as has happened in several other surprising Calosoma findings due to anthropic influence. However it would also seem that in this case C. peregrinator has had the opportunity to naturalize on the island.
Finally, it is interesting to note that, vice versa, the importation of C. peregrinator, among other Calosoma species, to Hawaii as potential biological control agents has been unsuccessful. These acclimatization attempts occurred over time from the early to mid-last century. More recently, very few isolated specimens have occasionally been found in Hawaii, near the port or airport of presumed entry, but stable populations have never been reported. (Liebherr et al. 2023).

Examined specimens and literature’s data
Dominican Republic. Pedernales: Oviedo (www.inaturalist.org).
Mexico. Baja California: La Cienega, Aguascalientes (Gidaspow, 1959: 258), Mexicali, San Felipe, Ensenada (www.inaturalist.org); Baixa California Sur: La Paz (www.inaturalist.org); Chihuahua: Pedernales (SB), Paso del Norte, Chihuahua city (sub C. ampliator Bates, 1891: 224), 73 km E of Chihuahua city, Yepomera, Colonia Garcia, Ciudad Jimenez (UASM), Pedro Meoqui (www.inaturalist.org); Coahuila: Saltillo (UASM), Juárez, Ramos Arizpe (www.inaturalist.org); Guerrero: Zihuatanejo (www.inaturalist.org); Durango: Lerdo (sub C. ampliator, Bates, 1891: 224), El Pino, Rodeo (UASM), Alemán, reserva La Michilia (Ball & Shpeley, 1991: 43), Durango city (UASM), Durango (sub C. ampliator, NMP), Peñón Blanco (www.inaturalist.org); Guanajuato: Jalapa (sub C. ampliator Bates, 1891: 224), Irapuato (UASM), Valle del Maiz (Bates, 1884: 21), San Miguel Allende (Gidaspow, 1959: 258); Jalisco: Puerto de Cineguillas (SB), Guadalajara (SB), Encarnacion de Diaz (UASM), Santa María de los Ángeles, Yahualica de González Gallo (www.inaturalist.org/ ); Mexico: Nevado de Toluca (www.gbif.org), Chapingo (Gidaspow, 1959: 258); Michoacán: Morelia (Gidaspow, 1959: 258); Nayarit: Volcan Ceboruco (UASM), El Torreon (Gidaspow, 1959: 258); Nuevo Leon: Monterrey (Gidaspow, 1959: 258), García, Santiago (www.inaturalist.org); Puebla: Tehuacán (www.inaturalist.org); Queretaro: Cadereyta (www.inaturalist.org/observations/2928325), Corregidora (www.inaturalist.org/obs. 29022234); San Luis Potosi: Sierra de San Miguelito (Bates, 1884: 21); Sinaloa: Los Mochis (AMNH), Guamúchil (SB), Culiacancito (SB), Culiacan UASM); Sonora: Navojoa (sub C. ampliator, AMNH), Valle de Yaqui (sub C. ampliator, Gidaspow, 1959: 268), Hermosillo (Gidaspow, 1959: 258), Santa Ana, Llano, Cananea, Agua Prieta, Nogales, Esqueda, Empalme, Peon, Moctezuma, Sierra San Luis, Cucurbe (UASM), Imuris. Alamos (http://madrean.org/), Arizpe (www.inaturalist.org/); Tamaulipas: Nuevo Laredo (sub C. ampliator Bates, 1891: 224), Valles de Anáhuac (www.inaturalist.org); Vera Cruz: Plan del Rio, Jalapa (Bates,1884:21), Xalapa (Jalapa) (sub C. ampliator, Gidaspow, 1959: 268), Tlapacoyan (www.gbif.org); Zacatecas: San Andres, Sombrerete (UASM), Guadelupe (Gidaspow, 1959: 258), Mazapil (www.inaturalist.org).
United States. Arizona: Prescott (Burgess & Collins, 1917: 75), S. Cruz County (EM, SB), Pima County (EM, SB), Yavapai County (http://bugguide.net/); Cochise County (SB), Chiricahua Mountains (UASM), Huachuca Mountains (YPM, discover.odai.yale.edu/), Maricopa County, Apache County (http://madrean.org/), Payson (www.gbif.org); California: San Diego (syntype of peregrinator ingens, NMNH), San Bernardino County (http://bugguide.net/), Riverside County (www.inaturalist.org/); Colorado: La Junta (Breuning, 1928a: 106), Cheyenne Mountain State Park, Colorado Springs, Lincoln County, Boulder (www.inaturalist.org); Kansas: Barber (www.gbif.org), Morton County (www.inaturalist.org); Nebraska: Scotts Bluff County (sub sayi; www.inaturalist.org/obs./28716297); Nevada: Stagecoach (www.inaturalist.org); New Mexico: Water Canyon (sub C. carbonatum; Snow, 1881: 39), Eddy County, Otero County, Dona Ana County (http://bugguide.net/), Luna county (UASM), Bernalillo County, Hidalgo County (http://madrean.org/), Portales, Grant County (www.inaturalist.org); Oklahoma (Bousquet, 2012: 236); Texas: Jeff Davis county (SB), Culberson county, Brewster county, El Paso county, Guadalupe Mountains National Park (UASM), Oldham County (www.inaturalist.org); Utah (Bousquet, 2012: 236), Grand County, San Juan County, Washington County, Lincoln County (www.inaturalist.org/).

Notes: Winged, attracted to light at night. Lives on grassland and pastures, from lowlands up to an altitude of 2300m. Occasionally, has been noted climbing tree and feeding on various caterpillar as Peridroma saucia, Malacosoma americanum and Lymantria dispar but probably secure most of its food near the ground (Burgess & Collins, 1917: 75). Considering the variety of habits in which the C. peregrinator lives, active individuals can be found almost all year round, at least from February to December, with a period of maximum activity between July and September, while in some areas it is possible to find adults overwintering in the soil.

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 United States, Arizona: S. Cruz County, Rio Rico, VIII.1973, Lenczy leg.

Calosoma (Camedula) peregrinator ♀ Guérin Méneville, 1844 United States, Arizona: S. Cruz County, Rio Rico, VIII.1973, Lenczy leg.

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 Etats Unis, Arizona (holotype of Calosoma forreri Géhin, 1885) (coll. Muséum National d'Histoire Naturelle, Paris)

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 Mexico. Chihuahua, (3447; 8100, coll. Pr. Poncetton – ex J. Clermont)

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 Mexico: Guadalajara

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 Mexico. Sinaloa: Guanamuchil

Calosoma (Camedula) peregrinator ♂ Guérin Méneville, 1844 Mexico. Sinaloa, 34 ml North los Mochis 27.VII.1943 (sub. Calosoma (Chrysostigma) ampliator, det. Gidaspow) (coll. American Museum of Natural History, New York)

Calosoma (Camedula) peregrinator ♀ Guérin Méneville, 1844 Mexico. Sonora Navojoa.VIII 3 1952 c&p Vaurie (sub. Calosoma (Chrysostigma) ampliator, det. Gidaspow) (coll. American Museum of Natural History, New York)