The presence of a broad front wing indicates that the photograph depicts a male tree cricket. I came across 4 tree crickets during August and September of 2003. Two of these were attracted to lights, 1 was singing in the shrubbery along the highway (I found this one after much searching at night), and 1 was on a vine leaf at Manzanita Spring during the daytime. These interesting insects while not uncommon, are inconspicuous because of their coloration and habits. I also found it difficult to determine which shrubs actually contained any males who were singing.
According to the Dr. Thomas Walker's "Singing Insects of North America" website, there are 18 known species of tree crickets in North America in 2 genera. Of these, there are 16 species of Oecanthus, 4 species having ranges which include or span the Park. Two of these species occur throughout much of the country, while the other have much more limited ranges (one of these has a disjunct distribution with populations known from opposite sides of the Park). Three of the 4 species are currently shown on the web site.
Based on Helfer's (1987) identification keys, the individual shown above belongs to the latipennis group of tree crickets. Stidham indicated that Oecanthus latipennis occurs in the Park but its presence here would be well west of the known distribution shown by Walker. My photograph does look like the picture of Oecanthus latipennis on the web site however; perhaps it is the species not shown.
References
Helfer, J.R. 1987
How to Know the Grasshoppers, Crickets, Cockroaches and Their Allies
Walker, T.
Singing Insects of North America
Note: This is a personal web site and is not affiliated with the National Park Service or Guadalupe Mountains National Park. Contact information for the author, Ron Lyons, is accessible through the Index Page referenced below. Thank you.