Description of Cornigamasus allotritosternus sp. nov. (Mesostigmata: Parasitidae) from China, with an emphasis on the ontogenetic development of setae Author Yao, Mao-Yuan Institute of Entomology, Guizhou University, Guizhou Key Laboratory for Plant Pest Management of Mountainous Region, Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture, P. R. China; Guiyang 550025. P. R. China. Corresponding author. E-mail: daochaojin @ 126. com; yitianci @ msn. com Author Guo, Jian-Jun Institute of Entomology, Guizhou University, Guizhou Key Laboratory for Plant Pest Management of Mountainous Region, Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture, P. R. China; Guiyang 550025. P. R. China. Corresponding author. E-mail: daochaojin @ 126. com; yitianci @ msn. com Author Yi, Tian-Ci Institute of Entomology, Guizhou University, Guizhou Key Laboratory for Plant Pest Management of Mountainous Region, Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture, P. R. China; Guiyang 550025. P. R. China. Corresponding author. E-mail: daochaojin @ 126. com; yitianci @ msn. com yitianci@msn.com Author Jin, Dao-Chao Institute of Entomology, Guizhou University, Guizhou Key Laboratory for Plant Pest Management of Mountainous Region, Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture, P. R. China; Guiyang 550025. P. R. China. Corresponding author. E-mail: daochaojin @ 126. com; yitianci @ msn. com yitianci@msn.com text Zootaxa 2020 2020-08-03 4821 3 462 486 journal article 8701 10.11646/zootaxa.4821.3.3 abe666bf-f37e-4916-81b9-5572d3645128 1175-5326 4400976 7AADF5E8-AB99-4693-8934-6BDF4C38324E Genus Cornigamasus Evans & Till, 1979 Type species: Gamasus coleoptratorum var. lunaris Berlese, 1882 Diagnosis. Female and deutonymph with separated podonotal and opisthonotal shields, male with holodorsal shield, a transverse suture in central region. Setae z5 of dorsal hexagon markedly different in form from j5 and j6 , usually thick, long and pilose distally. Tritosternum of female and deutonymph normal, but absent or biramous in male, if biramous, base reduced. Metasternal shields in female separated from sternal shield by an oblique suture. Genital shield of female triangular. Opisthogaster with rarely more than 15 pairs of setae. Seta al of palp femur setose, spiculate or rod-shaped, setae al1 and al2 of palp genu spatulate distally. Corniculi long and parallel, extending beyond anterior margin of palp trochanter, grooved to accommodate ‘salivary’ styli. Legs without spurs except for leg II of male. Notes. The diagnosis of Cornigamasus is based on the definition by Hyatt (1980) . The most important difference is that the tritosternum of the male, which is absent in known species ( Hyatt 1980 ; Ma 1986 ; Skorupski & Witaliński 1997 ), is biramous with a degenerated base in C. allotritosternus sp. nov. . Therefore, the genus diagnosis is modified slightly to accommodate C. allotritosternus sp. nov. .