There are two subspecies of box turtles in this range, the desert the ornate box turtles. The desert is found only in the westernmost part of the Trans-Pecos.
The ornate box turtles are found throughout most of Texas. The range ends about where the Big Bend begins, approaching the Davis and Chisos Mountains. This one is a female.
Terrapene ornata luteola
These specimens were collected near Van Horn. The female is from NW Presidio county on Hwy. 90, the male is from NE of Van Horn.
This picture is of a male. Notice the red eyes, which are characteristic of the males.
I found the female down the road from the male and placed her a few feet away from him. After a moment, he scurried over to her and inspected her, She had both ends of her shell tightly closed. He then started prodding her with his snout. She remained closed tight. He then proceed to nip at her shell, to no avail. This picture was taken when he mounted her on the front end. She remained unresponsive. After a moment he went to the other end and mounted again. This time she popped from her shell and tried to walk away, but he hung on successfully. Unfortunately, by this time I was out of film and was unable to capture the culmination of his efforts.