Trebacosa Dondale & Redner, 1981

Type species: Pirata marxi Stone, 1890

Differential diagnosis (see Dondale & Redner (1981) for the full diagnosis). Carapace with a characteristic pattern (Figs 1, 5–7): three parallel white lines, which do not touch. This is similar to those of Pirata Sundevall, 1833, but those have the white line converging in the thoracic region. The short sperm ducts are similar in the genera Pirata, Piratula Roewer, 1960 and Trebacosa . Females of Trebacosa can be distinguished from those of Pirata and Piratula by the position of the vulval chamber relative to the head of spermatheca (Figs 9, 16, 21). In Trebacosa, the HS is ectal and the VC is mesal, whereas in Piratula and Pirata the HS is positioned mesal relative to the VC. Trebacosa is seemingly unique by possessing the primary pores at the basis of the HS (Luis Piacentini – pers comm.). Males of Trebacosa can be recognized by the large angular median apophysis (Dondale & Redner 1981, Dondale 2005).