The family Walchiidae, one of three families of the superfamily Trombiculoidea sensu Wen, contains two subfamilies: Walchiinae sensu Wen and Gahrliepiinae sensu Wen. The subfamily Walchiinae may be further separated into two tribes: Walchiini and Schoengastielliini. Members of the tribe Walchiini are small to medium sized sand-mites with IP=344–800 and the following features: the scutum ranging from very small to medium size, pentagonal or short tongue-shaped, with uniform punctae but without scrobiculae and with only two pairs of scutal setae consistently (fSc=2AL 2PL), without accessory setae; sensillae expanded; SIF=4B/5B-N/B-3/ 2-2(1)1(0)1(0)0.0000; leg segments fSP=7.6.6 wihtout variation; pedogenualae fg(s)=2.1.1 in most species; fcx=1.1.1 or 1.1.2 in most species, but a few species with 3–6 coxalae III; some species characterized by one of hair-like claws reduced on each leg. Currently, the Walchiini contains 92 nominated species in 2 genera and 15 subgenera (including Wenia sg. n. and Zhangzia sg. n.). The genus Walchia is characterized by fT=4B and acuminated posterior angle, rarely rounded, whereas the genus Ripiaspichia is distinguished by fT=5B and rounded posterior margin. Hosts of the Walchiini are chiefly small ground rodents, insectivores and lagomorphs, rarely bats, deers and horses, and occasionally reptiles. They are pale coloured host-burrow dwellers. Two subgenera, Fainiella and Traudia, are intranasal parasites. Walchiiine sand-mites are essentially confined to the Old World, the largest number of species having been recorded from Southeast Asia. As yet, this tribe has not been reported from the Neotropical Region. A key to the genera and subgenera of the Walchiini is given.
Systematic and Applied Acarology
Vol. 7 • No. 1
Vol. 7 • No. 1