Melolonthidae Leach, 1817
Coenonycha acuta Cazier, 1943
Coenonycha ampla Cazier, 1943
Coenonycha barri Cazier, 1943
Coenonycha bowlesi Cazier, 1943
Coenonycha clementina Casey, 1909
Coenonycha clypeata Mcclay, 1943
Coenonycha crispata Mcclay, 1943
Coenonycha dimorpha Evans & Smith, 1986
Coenonycha fuga Cazier, 1943
Coenonycha fulva Mcclay, 1943
Coenonycha fusca Mcclay, 1943
Coenonycha globosa Mcclay, 1943
Coenonycha hageni Cazier, 1943
Coenonycha lurida Cazier, 1943
Coenonycha mediata Cazier, 1943
Coenonycha ochreata Evans & Smith, 1986
Coenonycha ovatis Mcclay, 1943
Coenonycha ovipennis Horn, 1876
Coenonycha pallida Cazier, 1943
Coenonycha parvula Fall, 1901
Coenonycha pascuensis Potts, 1945
Coenonycha purshiae Cazier, 1943
Coenonycha pygmaea Evans & Smith, 1986
Coenonycha rotundata (LeConte, 1856)
Coenonycha rubida Mcclay, 1943
Coenonycha santacruzae Evans & Smith, 1986
Coenonycha saylori Cazier, 1943
Coenonycha scotti Mcclay, 1943
Coenonycha sleeperi Evans, 1988
Coenonycha socialis Horn, 1876
Coenonycha stohleri Saylor, 1935
Coenonycha testacea Cazier, 1937
Coenonycha tingi Cazier, 1937
Coenonycha utahensis Mcclay, 1943