The Collaborative International Dictionary
Luciferin \Lu*cif"er*in\ (l[=oo]*s[i^]f"[~e]r*[i^]n), n. (Biochem.) any of several substances found in luminescent organisms (such as the firefly, Photinus pyralis) which, when oxidized, produces an almost heatless light. It was first isolated from fireflies, and is the source of the firefly luminescence. See also firefly luciferin
Firefly luciferin \Fire"fly` lu*cif"er*in\, n. (Biochem.) a type of luciferin produced by the firefly Photinus pyralis.
Note: Its structure has been elucidated, and chemically it is recognized as
4,5-Dihydro-2-(6-hydroxy-2-benzothiazol-2-yl)-4-thiazolecarboxylic
acid, C11H8N3O2S2. It has found use in a very
sensitive assay for ATP, in which concentrations of ATP
as low as 10^ -11 molar can be detected.
--[MI11]
Firefly \Fire"fly`\, n.; pl. Fireflies. (Zo["o]l.) Any luminous winged insect, esp. luminous beetles of the family Lampyrid[ae].
Note: The common American species belong to the genera Photinus (especially Photinus pyralis) and Photuris, in which both sexes are winged. The name is also applied to luminous species of Elaterid[ae]. See Fire beetle.
Wikipedia
Photinus pyralis, known by the common names common eastern firefly and big dipper firefly, is the most common species of firefly in North America. P. pyralis is a flying and light producing beetle with a light organ on the ventral side of its abdomen. This organism is sometimes incorrectly classified as Photuris pyralis, which likely results from mistaking the similar sounding genus Photuris.
The Photuris female may also lure a Photinus pyralis to be eaten to obtain spider-repellent steroids which Cornell researchers named "lucibufagins" in 1997. In males the light organ covers the entire ventral surface of the three most posterior segments and in females it only covers a portion of the third posterior segment. These fireflies are most noticeable around twilight, in the early part of the evening and hover close to the ground. The species' common name refers to the characteristic flight of the male, which flies in a J-shaped trajectory, lighting on the upswing. During flight, the J-shaped flight pattern is used in combination with patrolling flash patterns while seeking a mate. Their flashes are stimulated by light conditions, not by rhythmic impulses as originally thought