Abstract: 【Aim】 To observe and understand the main morphological characteristics and ultrastructure of different developmental stages of Chortoglyphus arcuatus. 【Methods】 Pure experimental population of C. arcuatus was fed with brewer’s yeast powder. Then, morphological characteristics of the mites at different developmental stages were observed in detail under the stereomicroscope, optical microscope and scanning electron microscope, respectively. 【Results】 Body color is bright pale red brown in adult stage, while milky white in other developmental stages. The idiosoma is firm with oval outline. The dorsal transverse groove is absent between the propodosoma and the hysterosoma. The chelicera is well developed with shears-shaped chela bearing distinct tooth and striae. The basal region of venter of gnathosoma has fine transverse striae. External vertical setae are clearly pectinate. All the body setae are short and smooth. The genital opening of the female is covered by paired and sclerotized genital plates between coxae Ⅲ and Ⅳ, of which posterior margins are smooth and bowlike curved. The penis of the male is long, curved and tube-liked, and located between coxaeⅠand Ⅱ. Anal suckers are funnel-shaped. Tarsal suckers are present. 【Conclusion】 Some characteristics or features, such as body color at egg, larval and nymphal stage, decoration on dorsal chelicerae and ventral gnathosoma, of C. arcuatus observed are the important additions to what described in early literatures and helpful for fast identification and taxonomic study of the mite and its relatives.

Key words: Chortoglyphus arcuatus, external morphology, micro-structure, ultrastructure, developmental stage