diurnal fireflies

Ellychnia is a genus of typical fireflies. The number of species in the genus is a matter of disagreement, either 17 or 24. Several species are placed in the genus Photinus by some authors. Regardless of their taxonomic placement, all 24 species occur only in North America.

Ellychnia fireflies are active during the day. They attract mates using chemical signals. In the spring they are often found on tree trunks, especially at sap flows on maple. They are reported to nectar on flowers in the fall, especially on goldenrods, but this needs corroboration.

Most Ellychnia species occur in the southwest. There are just three eastern species, Ellychnia autumnalis, Ellychnia lacustris, and Ellychnia corrusca. Each one is thought to be a species complex – a group of several closely related species. The taxonomy is uncertain. The distinction as separate species is supported by differences in genitalia, but there are wide variations in size as well as differences in seasonality and behavior. All three species are said to occur in Minnesota, but Ellychnia corrusca is the only species in the genus for which there are records in Minnesota.

Ellychnia are small to medium-sized beetles. Though called fireflies, they are non-luminous – neither sex has bioluminescent organs.

The eyes are small and spaced far apart. The antennae are slender and have 11 segments. The third and fourth segments are long. The last segment does not have a minute appendage at the tip.

The exoskeletal plate covering the thorax (pronotum) is roughly semi-elliptical. It is rounded in front and the rear angles are almost rectangular.

The turned under fold (epipleura) on the lateral margins of the hardened forewings (elytra) are well defined and moderately wide.

The legs are short and stout.

Sources

24, 27, 29, 30, 82, 83.

Location: La Salle Lake SNA