General: Fireflies, beetles in the family Lampyridae, are mostly bugs of the night in eastern forests and southern swamps, but a few species occur in the western U.S., including this species (Photuris spp.) that occurs in Glen Canyon National Recreation Area and Grand Staircase - Escalante National Monument. This species is tentatively identified as Photuris lucicrescens, but it might be an undescribed species. These photos were taken in Coyote Gulch at the spring just below Jacob Hamblin Arch. Keep an eye out for fireflies at night in other damp places, as these nocturnal flashers are known from few western places.

In most firefly species, males use their light-emitting organ (the white section on the abdomen) to flash during mating flights. Different species have different flash patterns, some quite elaborate, so when several species are flying together, females can tell the right males in the dark. Females also flash, but while sitting on vegetation rather than in flight.

In Coyote Gulch, fireflies have a simple flash pattern, perhaps because they are the only species in the area.

Fireflies in the genus Photuris can be recognized by the fact that the head and eyes can be seen from above; that is, they are not obscured by the pronotum (the shield above the head).

Fireflies in the genus Photuris are the "femme fatale" fireflies, a reference to the females mimicking the light signals of males of other firefly species to attract, catch, and eat them.