Urostylididae is a family of true bugs and is considered a basal or "primitive" family within the stink-bug lineage. They are found only in Asia. Older works used the spelling Urostylidae but this clashes with the name used for a protozoan family and a spelling correction (emendation) has been suggested that also avoids the confusion created by homonyms. The family name Urolabididae has also been used for some members in the past.[1]
This family has about 100 species, with distribution limited mainly to eastern Asia. Urostylidids are 4 to 15 mm and somewhat longer than broad with elongated legs, three tarsal segments, and a small head. The antenna has 5 segments of which the first is longer than the head. The base of the antenna has broad tubercles and has a ringed appearance. The simple eyes or ocelli, when present (Urolabida lacks ocelli[2]), are very close to each other. They show a wide separation between the hind and mid coxae on the underside. Other important family characters are the presence of a structure for stridulation, the stridulitrum on the first anal vein of the hind wing, and bristles on the claws. The female genital structure has nine gonocoxites that form a M or W-shaped sclerite. They suck plant sap.[3] [4] The male reproductive anatomy suggests close affinities to the Tessaratomidae subfamily Natalicolinae. The spermatheca has two pump flanges in two genera which is a feature found also in the Aradidae and Leptopodidae. Thus the phylogeny of the group is unclear but lies within the Pentatomoidea.[5] In the past the family was divided into two subfamilies, but one group, the Saileriolinae, has since been suggested as a distinct family, Saileriolidae, by at least two studies. The position of Saileriolidae within the Pentatomoidea is still unclear.[6] [7]