The article makes an attempt to trace the written sources and personal records of folklore texts and decipher the expression “I pity my butterfly-soul”, found in a dozen four-line songs, which in very close versions were recorded at the end of the 19th — beginning of the 21st centuries in the area of residence of the Kazan Udmurts (i. e. the modern-day Kukmor and Shoshmin dialectal areas of the Udmurt language). Ethnographers noted two names for ‘soul’ among the Udmurts: lul ‘souls of a living person’ and urt ‘souls of the deceased’ — in most modern dialects and modern printed sources, predominantly only the word lul (< Fug.) has survived to the present time, having a very wide range of meanings, overgrown with many derivatives and acting as part of a large circle of phraseological phrases. The soul urt (< Op.), often left a person’s body during sleep, even during their lifetime, in the form of various living creatures (mice, weasels, flies and most often butterflies), and the act of its returning after its wanderings, perhaps, gave rise to the expression “butterflysouls” (*bubyli-urt), which, due to the gradual withdrawal of the word urt from living speech, was transformed into the construction bubyli-lul using the widespread word lul, meaning ‘soul’ in all cases of its manifestation. The very expression of Bugyli lulme zhal’aśko (in variations) ‘I pity my butterfly-soul’ in the quatrain of the Kazan Udmurts, which, according to my information, was rarely or never performed as a song, presumably arose and remained in popular memory to designate the material hypostasis of the soul, sometimes appearing in this world, and, possibly, as a reminder of the frailty of man's earthly existence.