The genus Sigaus is endemic to New Zealand and with all but one species endemic to the South Island. Sigaus piliferus is currently the only representative of the endemic grasshopper genera found in the North Island. There are eight species with this genus. The genus Sigaus is easily distinguished from other genera within this family in New Zealand by the distinctive structures of the male genitalia. The epiphallus lophi are saddle-like in shape with the mesal protuberance of the lophus having a smooth, rounded outline. These structures are internal of the male genitalia.