It means silky. Serikos is silk and ulus is a diminutive. It is a genus of birds in the family Ptilonorhynchidae, which has four species (three endemic to New Guinea and one that is endemic to Australia). They are known as pergoleros.
Sericulus : Genus of passerine birds of the ptilonornorquid family that inhabit New Guinea and eastern Australia and are known as pergoleros.