Ten new species of the feather mite genus Trouessartia Canestrini, 1899 (Analgoidea: Trouessartiidae) are described from various passerines of the superfamily Passeroidea in Georgia: Trouessartia americana sp. n. from Setophaga americana (Linnaeus), T. helmitheros sp. n. from Helmitheros vermivorum (Gmelin, JF), T. mniotilta sp. n. from Mniotilta varia (Linnaeus), T. pensylvanica sp. n. from Setophaga pensylvanica (Linnaeus) (type host) and S. palmarum (Gmelin, JF), T. ruticilla sp. n. from S. ruticilla (Linnaeus), T. seiurus sp. n. from Seiurus aurocapilla (Linnaeus), T. tigrina sp. n. from Setophaga tigrina (Gmelin, JF) (Parulidae), T. passerinae sp. n. from Passerina caerulea (Linnaeus) (type host) and P. cyanea (Linnaeus), T. ciris sp. n. from P. ciris (Linnaeus) (Cardinalidae), and T. spizellae sp. n. from Spizella passerina (Bechstein) (Passerellidae). Based on a specific combination of morphological characters, all new species and six previously known species are arranged into a new species group capensis in the genus Trouessartia. The most important diagnostic characters of this species group include: in both sexes, the dorsal hysterosomal apertures are absent; in males, the postgenital plaque is well developed and genital setae g have cylindrical articulation rings; in females, the external copulatory tube is straight, stylet- or finger-like, and situated on the margin of the interlobar membrane, and the head of spermatheca has a semi-ovate extension without indentations. A key to all species referred to the capensis group is provided and host associations of this group with passerines are summarized and briefly discussed. It is hypothesized that this species group originated on the ancestors of New World nine-primaried oscines (Emberizoidea) and diverged in close relation with this group of hosts.