Scarce swallowtail Scarce swallowtail The scarce swallowtail ("Iphiclides podalirius") is a butterfly belonging to the family Papilionidae. It is also called the sail swallowtail or pear-tree swallowtail. Subspecies include: "Iphiclides podalirius feisthamelii" is sometimes treated as a valid species, "Iphiclides feisthamelii". Despite the name "scarce swallowtail", this species is quite common. The scarcity of United Kingdom migrants is responsible for the English vernacular name. This species is widespread in the East Palearctic ecozone and in most of Europe with the exception of the northern parts. Its range extends northwards to Lower Lusatia and central Poland and eastwards across Asia Minor and Transcaucasia
Comma (music) Pythagorean comma (PC) and the syntonic comma (SC) are basic intervals that can be used as yardsticks to define some of the other commas. For instance, the difference between them is a small comma called schisma. A schisma is not audible in many contexts, as its size is narrower than the smallest audible difference between tones (which is around six cents, also known as just noticeable difference, or JND). Many other commas have been enumerated and named by microtonalists The syntonic comma has a crucial role in the history of music. It is the amount by which some of the