Is this a Cerambycid in the San Bernardino Mtns?
Location: San Bernardino Mountains near Lake Arrowhead approx.5800’ elevation
February 22, 2011 12:08 am
Hello, several of my neighbors have found this insect in their homes this winter. Since many residents are worried about another bark beetle outbreak, they would like to know if this beetle will damage their trees.
Signature: Gina Richmond

Cedar Tree Borer

Dear Gina,
You are correct.  This is a Cerambycid or Longicorn beetle.  We do not recognize the species and browsing through BugGuide did not prove fruitful.  This photo taken from a screen shot is quite amusing to us, but we have no idea of scale.  How large is this Longicorn?  Hopefully, we will be able to provide you with a species identification.  Longicorns do have larvae that are wood borers, but very few species do considerable damage to trees.

Identification courtesy of Karl
Hi Daniel and Gina:
Your longicorn looks like a Cedar Tree Borer (Semanotus ligneus ligneous). This beetle sparked a very length discussion when it was posted on WTB? by Kathie Jones on February 5, 2007. Based on that exchange, you may want to check your new cedar furniture if you have any. Regards. Karl

Thanks Karl,
This is most curious.  Since the insect is being reported from several different homes, we wonder if there has been a range expansion, or if the Cedar Tree Borer may be a newly introduced species in California.  It would also probably require an expert viewing the actual specimen to determine if this really is a Cedar Tree Borer or some look-alike.

Comment from Brian, an entomologist
Make me wonder what is going on with this one???????
I agree it is most likely Semanotusbut to get it to species level by the photo would be hard to do. Better photo would be great.
Semanotus ligneus does occur in California but I have never seen one so red in color and the placement of the spots on the elytra does not seem just right.
This genus does include some exotics and it may be worthwhile for them to submit it to the state or an extension service.  Better safe than sorry. Far as I know the USA only has two species for this genus.
I would not guess cedar furniture but firewood since it is found in more than one home. Most likely wood from the surrounding area. Juniperus maybe? but that not a common species used for firewood.
Well thanks for peaking my interest. Hope its a native and not an exotic
As always keep up the great work!

Thanks so much for the information! I will forward this to the neighbors who have encountered the Cedar Tree Borer in their homes. I will check back to this site often as I really enjoy learning more about insects- what a great website,
All the best,
Gina Richmond

Location: California

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