The spider genus Spintharus occurs from the northeastern United States to Brazil, with one species found in Pakistan. It is very similar to the genus Thwaitesia, and both are similar to Episinus. Unlike Argyrodes, they have two setae in place of a colulus. Specimens of S. flavidus are variable in structure. Only some have an elevated eye region or humps on the anterior of the abdomen. Females of S. gracilis are 3.7mm long, males 2.3mm.