Thrixopelma lagunas sp. n. is the fourth species of the genus distributed in Peru. It is characterized by a prolonged embolus in the male (fig.4-5) and very simple receptacula seminis in the female (fig. 9). The scopula of metatarsus III extends over a third of the segment only. In T. pruriens Schmidt, 1998 it covers 2/3, in T. cyaneolum Schmidt, Friebolin & Friebolin, 2005 and in T. ockerti Schmidt, 1994, 1/2 of the metatarsus III. It differs by its dark brown colour from T. cyaneolum which shows a cyan brightness of carapace and extremities and from T. ockerti by its spermathecae which are pointed- caplike. The new species is closely related to T. pruriens also distri-buted in Peru.