Bloutjies (Lycaenidae) is die tweede grootste familie van vlinders (na vierpootskoenlappers), met ongeveer 4 500 spesies wêreldwyd. In die verlede was metaalvlerkies (Riodinidae) geklassifiseer as die subfamilie van die bloutjies (Lycaenidae), maar Riodinidae word tans as 'n afsonderlike familie binne die superfamilie Papilionoidea beskou. Sommige bronne verwys nog na bloutjies as die grootste vlinderfamilie (met meer as 6 000 spesies), omdat metaalvlerkies aanvanklik by die bloutjiefamilie ingesluit was. "World Butterfly Census (data collated by Hoskins from sources including Tolman 1997, Larsen 2005, Lamas 2004, d'Abrera 2001, Scott 1992, Preston-Mafham 1988, McCubbin 1971, Eliot/Corbet & Pendlebury 1992, Shields 1989, Ackery 1995, funet 2014, BoldSystems 2014, LepIndex 2014)". Adrian Hoskins (www.learnaboutbutterflies.com). Besoek op 4 April 2017. "Journal of the Lepidopterists' Society 43(3), 1989, 178-183 – World Numbers of Butterflies" (PDF). Lepidopterists' Society. Besoek op 4 April 2017. "Butterflies, Philip J. DeVries" (PDF). Milwaukee Public Museum: Center for Biodiversity Studies.