Genus Photinus

Author of genus is LaPorte, 1833. According to Wikipedia, which quotes the Catholic Encyclopedia, (article here) Photinus (died 376) was a fourth-century Christian (Arian) heretic. The connection with the beetle is not clear--perhaps both names simply have a common meaning.

Nearctica.com lists 34 species.

6-14 mm

The most frequently-noticed fireflies in eastern North America. Pronotum covers head completely (only partially in Photuris), legs short, stout and compressed. Eyes large, especially in male, light organs well-developed. Pronotum not ridged in center, often grooved (1). Elytral fold, seen from side, complete--left, as opposed to incomplete fold of Photuris--right (2):

Adults likely do not eat.

Have potent chemical defenses, primarily the steroid-like lucibufagins. These chemical defenses are known to make the beetles distasteful to jumping spiders and birds (Eisner et al., 1978), (3). Female Photuris are known to lure in males of this genus in order to consume them and obtain the defensive compounds (Eisner et al., 1997) (3).

Dillon, pp. 248-249 (key to genera), pp. 254-255, plate XXVI (1)

White, pp. 190-191, fig. 78, plate 3 (2)

Eisner, 2003, For Love of Insects (3).

Eisner et al., 1978. Lucibufagins: Defensive steroids from the fireflies Photinus ignitus and P. marginellus (Coleoptera: Lampyridae). Proc. Natl. Acad. Sci. USA 75: 905-908.

Eisner et al., 1997. Firefly “femmes fatales” acquire defensive steroids (lucibufagins) from their firefly prey. Proc Natl Acad Sci USA 94: 9723–9728.