P. reticulata is a tiny to medium-sized beetle. The males of this all-brown species are about long, have a short second antennomere (compared to the third) as well as large eyes. Unlike many firefly species found in the eastern and central United States,
P. reticulata males display a steady glow, instead of a species-specific flashing pattern. The light emitted by "blue ghost" fireflies appears to the human eye as blueish-white when observed at night from a distance, but bright green when examined at close range. This discrepancy in the observed color may be due to the
Purkinje effect. Males are capable of controlling each light segment independently and can vary the intensity of their glow. Female blue ghosts are wingless, unable to fly, and they are yellow and
paedomorphic, remaining in larval form through adulthood. They are also tiny, measuring only about long. ==Life cycle==