This particular specimen was submitted by a person who thought it came from a pine tree. The larval stage of these insects chews through dead and dying trees and some species develop in the stems of woody and herbaceous plants. Unlike some insects such as bark beetles that exist just under the bark of trees, metallic wood boring beetles can tunnel through any part of the tree including old wood. Larvae develop slowly and pupate under the bark. The adults chew a hole through the bark in order to emerge from the tree. Some species attack only dead or dying trees and some can attack dead limbs on otherwise healthy trees, and a few species can attack healthy trees. There are many species of metallic wood boring beetles (insect family Buprestidae) and many are iridescent in coloration and quite handsome insects. All of this being said, if you find a metallic green Buprestid then please make sure it is not the emerald ash borer (http://bugguide.net/node/view/27565/bgimage). This invasive species from Asia is devastating trees in the Midwestern U.S.A. and, while not known to be in Texas, has us on alert.