Polygonia comma Polygonia comma Polygonia comma, the eastern comma, is a North American butterfly in the family Nymphalidae, subfamily Nymphalinae. This butterfly is seasonally variable. The upperside of the summer form's hindwings are all black, whereas the winter forms hindwings are reddish orange. The underside of both forms is striped with dark and light brown. There is a silvery comma mark in the middle of the hindwing in both forms. Its wingspan is . The eastern comma may be spotted in woods near rivers, ponds, marshes, swamps, and other water sources. This butterfly seldom visits flowers, but rather feeds on sap, rotting
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