The books use the lack of a dark cross band as a key character for this species. This is to show that this species can, and often does, have such a dark band on the hind wing, even if it is a bit cloudy and light (in keeping with the genus). Another interesting point is that there is little size difference between males and females of most species of Circotettix, unlike most other genera of grasshoppers where females are usually considerably larger. (Compare the sizes of other C. undulatus that were caught in this same date and place.)

I took this photo in shadow, because it showed the black coloring better (without the backlighting and reflection from the sun).