Review of the Nearctic Claustropyga Hippa, Vilkamaa & Mohrig (Diptera, Sciaridae) with the description of three new species

The following new species are described from Canada: Claustropyga mirifica sp. n. from Quebec and C. spicea sp. n. and C. triloba sp. n. from the Yukon. C. aperta Hippa, Vilkamaa & Mohrig, previously known from Europe, and C. sim-plicis Hippa, Vilkamaa & Mohrig, previously known from Ontario, are recorded from Vancouver Island, British Columbia. C. auriculata Hippa, Vilkamaa & Mohrig, previously known from the Palaearctic region and from Alaska, and C. obtusidens Hippa, Vilkamaa & Mohrig, previously known from Europe, are recorded from the Yukon. The diagnostic characters of all the Nearctic species are discussed. In addition to the above- mentioned species, the Nearctic fauna of Claustropyga includes C. acanthostyla ( Tuomikoski), C. elizabethae Hippa, Vilkamaa & Mohrig and C. subcorticis ( Mohrig & Krivosheina). A key to the known species of Claustropyga is given.