Sorry I didn't respond to your other photo but I've been busy this week.

Your beetle definitely has the elytral apices drawn out to distinct spines. Also, what look like spines on the antennae are actually long black setae. You can see those in other photos of Placosternus on the guide. A better way of thinking about antennal spines in this group is whether the antennal segments are produced into spines, that is, are the antennal segments rounded at the corners or produced (=pointed).

I'm not sure how far longhorned beetles may fly from their host plants, but from experience and anecdotal evidence, they can probably fly pretty far.

There are no BugGuide records for either species in the genus Placosternus in Travis County. We were referring to the following by Mike Quinn when trying to identify this species:

https://bugguide.net/node/view/1473899

We'd appreciate more detail on your identification. Thanks!

First of all, I had forgotten that M. caryae can emerge in the fall in Texas. That forced me to go look at your photo again very carefully and compare with photos of both taxa. The big character you can see in your photo that eliminates M. caryae is the presence of a band of pubescence along the anterior margin of the pronotum. This character is lacking in M. caryae. Another character that's a bit difficult to discern in your photo is the lack of spines on the basal antennal segments. They should be there for M. caryae, but not for Placosternus. You can see them in the series of photos at your link by Mike Quinn.

Having said all that, I did make an assumption that it couldn't be M. caryae because of the time of year (bad assumption for Texas but good everywhere else in the range), by the overall color pattern (protonum color pattern very important here) and by the red legs and antennae. It was good to go back and really look at the keys and the descriptions.

If you have any other photos of this beetle, look for the spines on the antennal segments (you shouldn't find them) and look for a prominent spine at the apex of each elytron. I think I can see the spine of the left elytron, but can't say for sure.

Thanks, Brady! We added another photo that shows some spines on the antennae. Also, according to the description of M. caryae, in 2020's Common Insects of Texas (Abbotts)... "numerous yellow bands across elytra; second one from base interrupted on side", which you can see in the photo.

We may need to get the illustrated key to wood-boring beetles you reference.