| abstract | Eleven species of the genus Euschoengastoides, 8 of them new, are described from western North America: Trombicula hoplai Loomis, type species; E. imperfectus (Brennan and Jones) comb.n.; E. ryckmani Brennan; E. annectens sp.n. (type locaity, 13 km SSE Alamos, Sonora, Mexico, type host Perognathus artus); E. arizonae sp.n. (type locality, 2.5 mi. E Sasabe, Pima Co., Arizona, type host Onychomys torridus); E. expansellus sp.n. (type locality, 18 m S Guamuchil, Sinaloa, Mexico, type host Perognathus pernix); E. neotomae sp.n. (type locality, Cottonwood Spring, Riverside Co., Calif., type host, Peromyscus crinitus); E. opimus sp.n. (Type locality, 10 km S Puertecitos, Baja Calif. Norte, Mexico, type host, Perognathus formosus); E. tanigoshii sp.n. (type locality, 11 km S, 3 km W Naco, Sonora, Mexico, type host Perognathus intermedius); E. tumidus sp.n. (type locality, 13 km SSE Alamos, Sonora, Mexico, Type host Peromyscus eremicus); and E. webbi sp.n. (type locality, 1 km NW Las Arrastras, Baja Caif. Norte, Mexico, type host Perognathus fallax). The genus is recorded from seven western states of the United States and nine states of northwestern Mexico. Recorded hosts consist of 1 lizard, 2 bats, 483 rodents, and 1 rabbit. Most of the larvae are from heteromyid and cricetid mice and rats. The larvae were taken throughout the year but were more abundant in the summer. The larva of each species is figured and described, the localities are mapped, the hosts are listed, and a key for the larval stage is provided. |