Unknown tiny black beetle borers on Crepe Myrtle in Texas

Help! We just transplanted a VERY LARGE (30+ ft) Crepe Myrtle last fall and recently noticed small gun shot-like borer holes with tiny (.5 mm) mostly black/copper beetles running in and out of the holes. The beetle is slightly retangular rather than roundish.
Most of the holes are close to the base of the tree.

Our Crepe Myrtle hasn't any new spring growth at all though the neighboring Myrtle's are starting to fully leaf out.The trunk and limbs are all very green and appear OK, just delayed in growth because of transplant shock (I am assuming that is why it is being attacked by borers)
I have looked online and the closest beetle I can find (in appearance) is the Banded Elm Borer. They are not supposed to be in Texas though and I believe they are larger than my critters.
I am afraid if left unchecked these borers might lead to the demise of this beautiful tree. Any advice on how to treat this problem would be appreciated!
Thanks!

 

Take samples to local Cooperative Extension office. Looking online, in future I would try T.A.M.U. Hort. web site.