Genus Megalybus Philippi, 1865: 641. Type species: Megalybus pictus Philippi, 1865; by present designation. = Megalybus Westwood, 1876: 511 (posterior homonym of Megalybus Philippi, 1865). Type species: Megalybus pictus Westwood, 1876 (= Megalybus pictus Philippi, 1865); by present designation. Refs.: Schiner, 1868: 141 (syn. of Thyllis); Reed, 1888: 15 (cat., as Thyllis); Hunter, 1901: 151 (cat., as Thyllis); Kertész, 1909: 2 (cat. as Thyllis); Cole, 1918: 64 (wing, diff. Villalus), 1919: 4,5,7,8,9 (notes); Edwards, 1930: 188 (in key), 189–191; Stuardo, 1946: 101 (cat.); Winterton et al., 2007: 812 (list); Gillung & Winterton, 2011: 24 (in key); Schlinger et al., 2013: 62 (in key). crassus Philippi, 1865: 642, pl. XXV fig. 19. Syntypes: female, Valdivia (no type specimens deposited in MNNC). Dist.: Valparaíso (Petorca: fundo Talanquén; Quillota: Cuesta El Melón; Valparaíso: El Salto, Rodelillo); Metropolitana (Cordillera: El Canelo, El Manzano; Santiago: El Arrayán, Lo Aguirre); Biobío (Arauco: Parque Nacional Nahuelbuta sector Cabrerío; Ñuble: Las Trancas at Puente Torrealba, Piedras Comadres, Puente Marchant); La Araucanía (Cautín: cerro Ñielol); Los Ríos (Valdivia: San Juan, Santo Domingo); Los Lagos (Llanquihue: Casa Pangue, Ensenada, Puerto Varas). Refs.: Reed, 1888: 289 (cat., as synonym of Thyllis philippii Schiner); Hunter, 1901: 151 (cat., as synonym of Thyllis philippii Schiner); Cole, 1919: 58, 60 (original description transcribed); Edwards, 1930: 190 (fig. 12), 192 (as valid species, male, female, redescription, synonymy); Ruiz & Stuardo, 1936: 318 (distr.); Stuardo, 1946: 101 (cat., synonymy). = Megalybus gracilis Philippi, 1865: 643. Syntypes: female, Valdivia (no type specimens deposited in MNNC). Schiner, 1868: 144 (as Thyllis); Reed, 1888: 289 (as Thyllis); Kertész, 1909: 2 (as Thyllis); Hunter, 1901: 151 (cat.); Cole, 1919: 60 (transcription of original description); Edwards, 1930: 192 (as synonym of M. crassus). = Thyllis philippii Schiner, 1868: 144. Syntypes female, Valdivia (NMW?). Reed, 1888: 289 (cat.); Hunter, 1901: 151 (cat.); Kertész, 1909: 3 (as valid species of Thyllis); Edwards, 1930: 192 (as synonym of M. crassus). = Megalybus gracilis Westwood, 1876: 512, pl. V fig. 5 (not Philippi, 1865). Syntypes: San Juan (UMO); Kertész, 1909: 2 (as synonym of M. gracilis Philippi); Edwards, 1930: 192 (as synonym of M. crassus). obesus Philippi, 1865: 642 –643. Holotype: female, Corral (no type specimen deposited in MNNC, presumably lost). Dist.: Coquimbo (Elqui: La Serena); Metropolitana (Chacabuco: Caleu; Cordillera: El Canelo, El Peñón, La Obra, Reserva Nacional Río Clarillo; Santiago: Lo Aguirre—on flowers of Trevoa trinervis Miers.); Biobío (Arauco: Parque Nacional Nahuelbuta; Ñuble: Las Trancas, Los Lleuques, Puente Marchant, San Fabián de Alico—on flowers of Castanea sativ a); Los Ríos (Valdivia: Corral, San Juan); Los Lagos (Llanquihue: Casa Pangue—on flowers of Chrysantemun leucanthenum and various shrubs, Ensenada—on flowers of Berberis; Osorno: Antillanca). Argentina: Neuquén (Lago Queñi, Paso Puyehue (actually Paso Cardenal Samoré)), on flowers of Lathyrus multiceps Clos). Refs.: Reed, 1888: 289 (cat., as Thyllis); Kertész, 1909: 3 (as Thyllis); Hunter, 1901: 151 (cat.); Cole, 1919: 60 (original description transcribed); Edwards, 1930: 1 91–192 (as Megalybus, male, female, redescription, synonymy); Stuardo, 1946: 101 (cat., synonymy); Stuardo, 1980: 97 (collect data); Devoto, 2006: 40, 69, 96 (collect data). = Megalybus tristis Philippi, 1865: 643 –644. Syntypes: male, San Juan (no type specimens deposited in MNNC). Reed, 1888: 289 (cat., as Thyllis); Hunter, 1901: 151 (cat.); Cole, 1919: 60 –61 (original description transcribed); Edwards, 1930: 191 (as synonym of M. obesus). = Megalybus tristis Westwood, 1876: 512 (not Philippi, 1865). Syntypes: male, San Juan (UMO); Kertész, 1909: 3 (as valid species of Thyllis); Edwards, 1930: 191 (as synonym of M. obesus). pictus Philippi, 1865: 642. Syntypes: Santiago, female (no type specimens deposited in MNNC). Dist.: Valparaíso (Marga Marga: Marga Marga, Parque Nacional La Campana sector Granizo; Petorca: Putaendo; Valparaíso: El Salto, San Gerónimo); Metropolitana (Chacabuco: Caleu; Cordillera: El Canelo—on flowers of Oxalis sp., El Manzano, La Obra—on Haplopappus sp., Quebrada El Purgatorio; Maipo: Rangue; Santiago: cerro La Provincia, cerro Manquehue—on flowers of Stachys albicaulis Lindl., cerro San Cristóbal, Lo Aguirre—on flowers of Trevoa trinervis Miers. and Podanthus mitiqui Lindl., Peñalolén, Santiago; Talagante: Talagante—on flowers of Azara dentata Ruiz et Pavon); O’Higgins (Colchagua: Chomedahue); Maule (Talca: Cumpeo); Biobío (Concepción: Concepción; Ñuble: Puente Marchant, Termas de Chillán); Los Ríos (Valdivia: San Juan); Los Lagos (Llanquihue: Casa Pangue, Puerto Varas; Chiloé: Castro). Argentina: Neuquén (Confluencia Traful, Lago Queñi, Lago Tromen, Paso Puyehue (actually Paso Cardenal Samoré), Villa Traful. on flowers of Budleja globosa Hope, Embothrium coccineum J. R. Forst. & G. Forst., Senecio zosterifolius Hook. et Arn.). Biology: reared from Amaurobiidae (Schlinger, 1987). Refs.: Reed, 1888: 289 (cat., as Thyllis); Hunter, 1901: 151 (cat.); Kertész, 1909: 3 (as Thyllis); Cole, 1919: 58 (original description transcribed); Edwards, 1930: 193 (as Megalybus, synonymy, female variability); Stuardo, 1946: 101–102 (cat., synonymy); Stuardo, 1980: 97 (collect data); Devoto, 2006: 69, 96 (collect data). = Megalybus subcylindricus Philippi, 1865: 644. Holotype: male, Valdivia, San Juan (no type specimen deposited in MNNC). Reed, 1888: 289 (cat., as Thyllis); Kertész, 1909: 3 (as valid species of Thyllis); Hunter, 1901: 151 (cat.); Cole, 1919: 61 (original description transcribed); Edwards, 1930: 193 (as synonym of M. pictus). = Megalybus pictu s Westwood, 1876: 511, pl. V fig. 4 (not Philippi, 1865). Syntypes: female, Chile (UMO). Kertész, 1909: 3 (as synonym of M. pictus Philippi). = Megalybus subcylindricus Westwood, 1876: 512 –513 (not Philippi, 1865). Syntypes: Valdivia (UMO); Edwards, 1930: 193 (as synonym of M. pictus). = Megalybus gracilis Cole, 1919: 59 (fig. 1), 61–62 (misidentification, not Philippi, 1865; not Westwood, 1876); Edwards, 1930: 193 (as synonym of M. pictus).

Published as part of González, Christian R., Elgueta, Mario & Ramirez, Francisco, 2018, A catalog of Acroceridae (Diptera) from Chile, pp. 427-440 in Zootaxa 4374 (3) on pages 428-430, DOI: 10.11646/zootaxa.4374.3.6, http://zenodo.org/record/1155465