Firefly systematics, as with many i

Firefly systematics, as with many insects, are in a constant state of flux, as new species continue to be discovered. The five subfamilies listed above are the most commonly accepted ones, though others, such as the Amydetinae and Psilocladinae, have been proposed. This was mainly done in an attempt to revise the Lampyrinae, which bit by bit had become something of a "wastebin taxon" to hold incertae sedis species and genera of fireflies. Other changes have been proposed, such as merging the Ototetrinae into the Luciolinae, but the arrangement used here appears to be the most frequently seen and stable layout for the time being. Though most groups appear to be monophyletic, some (e.g., the tribe Photinini) are perhaps better divided.

There seem to be two groups of subfamilies: one containing many American and some Eurasian species in the Lampyrinae and Photurinae, and one, predominantly Asian, made up from the other subfamilies. While the subfamilies as understood here are, in general, monophyletic, there are still a few genera that need to be moved about for the subfamilies to accurately represent the evolutionary relationships among the fireflies.

The Rhagophthalmidae are a glow worm-like lineage of Elateroidea. They have in the recent past usually been considered a distinct family, but it is still disputed as to whether this is correct. Indeed, they might be the only close relative of the puzzling firefly genus Pterotus, which sometimes is placed in a monotypic subfamily.

The genus Phausis, usually placed in the tribe Photinini of the Lampyrinae, might represent another rather distinct lineage instead.