Apical flagellomeres brown not distinctly paler than subapical flagellomeres; vertex of head entirely melanic; fore wing mostly infuscated; pronotum entirely pale (yellow to orange); fore tibia entirely pale (yellow to orange); mesoscutum entirely pale; anterior transverse carina of propodeum not reaching the lateral margin; median tergites entirely pale (yellow to orange); median syntergite 2+3 1.1 times longer than wide.

Holotype: female. Body length 4.4 mm. Fore wing length 5.1 mm. Fore wing mostly infuscated. Pronotum entirely pale (yellow to orange). Scutellar sulcus with one median longitudinal carina. Median areola of propodeum with well-defined margins. Anterior transverse carina of propodeum not reaching the lateral margin. Lateral longitudinal carinae of median tergite 1 well-defined. Median syntergite 2+3 1.1 times longer than wide. Ovipositor about same length as body.

Similar to holotype except for face. Face usually paler than holotype.

Lytopylus alfredomainieri is named in honor of Alfredo Mainieri in recognition of his participation in the collaborative development of the ICE-ACG geothermal project of Pailas II, northwestern Costa Rica.

Reared five times from two species of Olethreutes (Olethreutinae, Tortricidae) leaf-tiers feeding on mature leaves of Meliosma glabrata (Sabiaceae) in ACG cloud forest edge at 1220 to 1276 m elevation.

Holotype ♀: Costa Rica, Guanacaste, Sector Cacao, Sendero Derrumbe, Area de Conservación Guanacaste 10.92918N -85.46426W 1220m., Manuel Pereira coll., food plant: Sabiaceae Meliosma glabrata, host caterpillar: Tortricidae, Olethreutinae, Olethreutes Janzen188, coll. date: 2/2/2009, parasitoid eclosion date: 3/19/2009, DHJPAR0035525. Paratypes: [the following have the same data as the holotype except as indicated] ♂, DHJPAR0035519. ♀, DHJPAR0035513. ♂, Sector Pailas Gemelos, 10.76928N -85.34662W, 1276m., Jose Cortez coll., host caterpillar: Olethreutes Brown22, coll. date: 10/7/2009, parasitoid eclosion date: 11/2/2009, DHJPAR0038251. [same as previous except eclosion date] ♂, parasitoid eclosion date: 11/1/2009, DHJPAR0037861.