Olinga fumosa is a species of caddisfly belonging to the family Conoesucidae. The species was first described by Keith Arthur John Wise in 1958, and is endemic to New Zealand.
The species was identified by Wise in 1958, based on a specimen collected from Waitati in 1917 by C. E. Clarke.[1] No further specimens of the species were discovered until entomologist Brian H. Patrick discovered further specimens in 1992. Patrick confirmed that the species was distinct from other members of Olinga, based on behavioural differences and the apparent inability to hybridise with O. feredayi.
Wise's original text (the type description) reads as follows:
Males have a wingspan of, with females larger at .
Wise noted that the species was visually similar to O. feredayi, but could be identified by O. fumosa being smaller, darker in colour, differences in genitalia and the seventh sternite.
The species is endemic to New Zealand, found in the vicinity of Dunedin in the Otago Region and South Canterbury on the South Island of New Zealand.