Etymology : The specific name is derived from the Latin word folium, leaf, and refers to the shape of urtica- ting setal patch on the dorsum of the abdomen, which is similar to oak leaf.
A female of Cyriocosmus giganteus Kaderka 2016 is described and illustrated for
the first time, a new diagnosis of this species is proposed. Cyriocosmus paredesi sp.
nov. from Quebrada Putuiman (Marañon River) and Cyriocosmus foliatus sp. nov.
from Umaral near Iquitos, both from Loreto Department in Peru, are described,
diagnosed, illustrated and keyed. The male of Cyriocosmus sellatus (Simon 1889)
from Rio Blanco, the tributary of Rio Tahuyao, Loreto Department in Peru, is redescribed
and figured. The distribution area of this species is updated, and difficulties
in the identification of this species are discussed.