Subject: What’s this bug?
Location: Western Washington state
May 24, 2015 8:03 pm
I found this bug on the side of my house in western Washington state. It’s been relatively cool and it’s near the end of May. The red “eyes” are fascinating. Thanks for your time. Kirsten
Signature: However you’d like

Winter Dark Firefly

Winter Firefly

Dear Kirsten,
We believe we have correctly identified your beetle as a relative of the Winter Firefly,
Ellychnia corrusca, thanks to a posting on Arthur Evan’s What’s Bugging You? site where it states:  “Winter dark fireflies are mostly dull black, but the sides of their flattened, shield-like midsections are marked with yellow, orange, or reddish arched bands. Their soft, pliable wing covers are clothed in short, fine, golden hairs.  Mature larvae pupate in dead logs, especially pines. Adults emerge in late summer and fall and are sometimes encountered on trees or on the flowers of goldenrod and other asters. As temperatures begin to drop, they seek protected places under bark for the winter. The beetles reappear on late winter and early spring days, either resting on bark or circled around sap flows on maples like cattle around a trough.  Like their more familiar cousins of summer, winter black fireflies are bioluminescent, at least for a while. Both the larval and pupal stages produce their own light. Even freshly emerge adults maintain this youthful glow, but as the beetles grow older they lose their light-producing organs.”  Since that is a mostly eastern species, we believe your individual is a member of the same genus.  A related species in the genus is Ellychnia facula, which according to BugGuide is found in the:  “Rocky Mountains from southeast British Columbia to Idaho.”  Your individual might also be Ellychnia greeni, which according to BugGuide is:  “Found along the west coast from southern British Columbia to northern California.”

Location: Western Washington

Leave a Reply

Your email address will not be published. Required fields are marked *