A new laelaptid mite collected from Yicheng County, Shanxi Province in Nov. 1995 off Apodemus speciosus is herewith described as follows: Laelaps shanxienses sp. nov. Diagnoses The new species described is allied to Laelaps nuttalli but is distiguishable by the following characters:1) the distance between Ⅵ 4 longer than that of Ⅵ 1; 2) S 8 is as 2/3 long as S 7; 3) the sternal plate is pretty long with a deep concave at its posterior margin. Female Elliptical in shape, 723μm long and 550μm width. Dorsal plate 696 μm long and 528μm width, almost covered over the dorsal part with 39 pair of spiculate setae. S 8 is as 1/2 long as M 11 (Fig. la).Terminal part expanded of pilus dentilis of digitus fixus of chelicera with an acuminate apex, much similar to that of Laelaps turkestanicus (Fig. lc).Middle anterior margin of sternal plate slightly narrowed (122 μm long), and 165 μm in length at the place of St 2, with a deep concave at the posterior margin, the top line of this concave reached the base of St 3( Fig. 1b) Apex of St 1 not reached the posterior margin of sternal plate, while that of St 2 extended beyond the margin. A pair of metasternal plate located at the place between the coxae of leg Ⅲ and leg Ⅳ. Epigynial plate 310 μm long, with an extreme width at the base line of Ⅵ 3(119μm). The distance between Ⅵ 4 110 μm, much longer than that of Ⅵ 1 (80μm). Metapodal plate ovoid in shape, 8-9 pair of epithelial setae on the ventral epithelium. Anal plate 156 μm long and 140 μm width. Adanal setae located at the posterior margin line of anal pore with apexes reaching the base of postanal seta. A spiniform seta and a spiculate seta set on the coxae of leg Ⅰ, leg Ⅱand legⅢ, with the spiculate seta located at the anterior margin of the coxa, while only a spiculate seta set on the coxa of legⅣ. Holotype ♀, collected from Yicheng County of Shanxi Province in Nov. 1995 off Apodemus speciosus, deposited in the Collections Hall of the Institute of Microbiology and Epidemiology, Academy of