Ed. Note: We have never made any of the Prionid Beetles a Bug of the Month, and summer is the season for the various species from coast to coast.  California has the California Prionus and the Eastern states have the Broad Necked Root Borer.  Many Prionids exhibit distinct sexual dimorphism, with the smaller males having more pronounced antennae.  Many females are practically or totally flightless, and males are attracted to lights at night.  Here is a recent letter.

Large beetle in NY
Location: Long Island, New York, USA
June 28, 2011 5:48 pm
I don’t think I’ve seen a bug this big in New York before. It’s slowly walking around my sidewalk and sticking its butt up in the air like this, with a yellow thing that is protruding and retracting.
Signature: J

Broad-Necked Root Borer

Hi J,
Your insect is a female Broad-Necked Root Borer,
Prionus laticollis, and the yellow thing is her ovipositor which is used to lay eggs.  According to BugGuide:  “Eggs are inserted into ground (or under litter) in groups. Larvae tunnel downward to feed on living roots of a variety of trees and shrubs. At first they may feed on bark, but then proceed to hollow out small roots.”


Broad Necked Root Borer



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Location: New York

4 Responses to Bug of the Month July 2011: Broad-Necked Root Borer

  1. esbuzz says:

    well i see this pic of the broad-necked root borer & says they’re in new york or the east coast. mine was found in northern california and is the size of my palm. is this normal or heard of?

    • bugman says:

      There are several related species in California, like the California Root Borer and the Ponderous Borer.

  2. voltron7 says:

    there is also an organ on the ovipositor that releases a scent to attract mates according to a similar post I made for i.d request on Bug Guide…

  3. Stephanie says:

    Do they kill the trees?

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