Male Broad Necked Root Borer

Subject: Mystery prionid on Cape Cod
Location: Eastham, Massachusetts
September 6, 2016 3:37 pm
Hello there,
We found several of these beetles at our rental house this summer in Eastham, MA. The ones we saw were in the 2″ range and came out at night – they appeared to be attracted to our porch light. The days we were seeing them were the first week of August but I don’t know how long before or after they were around. They look to be some form of prionid beetle but I am unsure as to species.
Signature: Laura

Male Broad Necked Root Borer
Male Broad Necked Root Borer

Dear Laura,
This looks to us like a male Broad-Necked Root Borer,
Prionus laticollis, and according to BugGuide:  “Pronotum as broad, or almost as broad, as base of elytra. Very dark. Elytra have irregular punctures, and each elytron has three indistinct longitudinal ridges. Pronotum has three blunt lateral teeth on each side. Antennae have 12-13 segments. Female much larger than male. The former is reported to be flightless, or nearly so. Males are attracted to lights.”


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