Late in the season Peucetia viridans is prone to change its colour from predominantly green to paler yellow, typically with streaks of reddish, suggesting degradation of the tetrapyrrole pigment in the blood.
The description highlights that as the season progresses, *Peucetia viridans* experiences a decrease in its blood's tetrapyrrole pigment, which is responsible for its green color and can be observed as streaks of red.