Synonyms and other taxonomic changes
Trimerotropis saxatilis McNeill 1900, described from Union County, Illinois
Pseudotrimerotropis saxatilis (McNeil)Kirby 1919. [Here Kirby listed T. verruculatus Thomas as a synonym - was probably an editing mistake.]
?Trimerotropis diversellus Hebard, 1928, described from Lower Geyser Basin, Yellowstone National Park, 7200 ft., Wyoming [relationship is very close, but needs further study]
Explanation of Names
There are two species listed as "Lichen Grasshopper". This one is eastern, the other in southern Arizona, and they look quite different.
Small to medium sized, slender, shades of gray, light brown, reddish, or green with black or dark brown speckling and dark cross bands across tegmina. Hind tibiae yellow occasionally to brownish. Hind wing yellow with dark band that is widest near outer margin of wing.
East of Great Plains it is not to be confused with any other species, but further west it may occur in close proximity to both Trimerotropis pallidipennis and T. salina, which are closely related and very similar.
T. saxatilis is found on rocks, usually outcroppings, ledges, ridge tops, etc. T. salina is on alkali seeps and flats, or similar areas around lake shores. T. pallidipennis isn't habitat specific; it is happy as long as the area is open, at least somewhat bare, and sunny. T. saxatilis is generally smaller than either of the others, with the pronotum proportionately shorter. The wings are shorter and proportionately broader, and usually a less translucent and of a paler shade of yellow than T. pallidipennis; the black band across the hind wings averages wider in T. saxatilis, more irregular in outline, and does not curve around the outside of the wing as far toward the base. T. pallidipennis usually has a proportionately smaller head.
T. salina is proportionately similar, but averages larger, and in some populations the wings average longer. In most of the overlap area T. salina usually has a much broader black band across the hind wings, which follows along the outer margin nearly to the base of the wing.
Western specimens generally look more like T. salina and T. pallidipennis in color and pattern than do eastern specimens. It is possible that the western type is not the same species as the eastern, but there is little evidence to support or to dispute this idea.
The slightly smaller T. diversellus from the Yellowstone area in Montana and Wyoming is extremely similar, and probably is just a local variant of T. saxatilis. It favors calcium encrusted areas near and in geyser fields. Differences are trivial, mainly it is of a smaller average size with the wing band averaging slightly wider (still narrow toward the front of the wing), and the band usually following around the outer margin nearly to the base.
In New Mexico, Colorado, Wyoming, and Nebraska, T. saxatilis sometimes occurs alongside of T. fratercula. The pronotum of T. fratercula usually has a sharper angle where the lateral lobes meet the top. It has a less contrasting pattern. On the distinctly broader hind wings the inner edge of the dark cross band is usually straight, forming a sharp angle with the almost completely offset and longer spur; the tip of the wings is more often darkened. In some populations, the hind tibiae and/or wings of T. fratercula may sometimes be somewhat greenish or even bluish. T. fratercula makes a much sharper, somewhat louder snapping sound in rapid series of short (usually two note) bursts when flying, and the sound is distinctly harsher and different from that produced by T. saxatilis. T. fratercula is a yellow-winged & legged version of T. cyaneipennis.
Western Carolinas and Georgia westward to central Texas, northeastern New Mexico, eastern Colorado, and eastern Wyoming. Perhaps in se. Montana (needs verification). Primarily in south Appalachians, Ozarks, Ouachitas, and isolated rock outcroppings on the Great Plains, west to the east base of the Rockies. Very common on the first "hogbacks" where the Great Plains meet the Rockies in Colorado and between Cheyenne and Laramie in Wyoming.
Confusion in the northern Rockies and Great Plains (north of Wyoming and Montana) makes it uncertain where the limits of the distribution for T. saxatilis lie. It reaches north at least into South Dakota.
Exposed sunny rock outcroppings and ledges. Type of rock seems largely unimportant, though very dark rocks such as basalt seem to not be inhabited. Habitats are most often limestone, conglomerate, sandstone, or granite, and are often lichen encrusted.
Overwinters as eggs, which hatch in spring. Adults late spring or early Summer until frost.
The coloration is highly variable from individual to individual, but tends to match the rocks upon which the insects live. Green pigmented specimens are quite striking. Such green specimens apparently do not occur west of extreme eastern Oklahoma and Kansas.
In the past, western specimens from the Great Plains and Rockies have been mostly mistaken for T. pallidipennis or T. fratercula, and in Texas for T. salina. T. saxatilis is described and figured well in Beamer's "Grasshoppers of Kansas" on p. 81, 114, & 115, but is called T. vinculata.
The insects are restricted to their rocky habitats, and will rarely fly away from them even when chased, either flying to another rock outcrop or circling back to the same one. They will just as happily land on a vertical or overhanging rock face as on a horizontal one. They often produce an interrupted buzzing crepitation when flying.
'The North American Grasshoppers' vol. II - Daniel Otte, 1984
'Orthoptera of North-eastern America' - W. S. Blatchley, 1920
'Grasshoppers of Kansas
: Part II' - Bulletin of the University of Kansas Biological Series 18(2), Raymond Beamer, 1917