As a loose rule of thumb, where both species occur in the same area, S. shoshone tends to like moist wooded or marshy bottomland and riparian areas and is the most likely of the two to move into urban and irrigated agricultural areas nearby. S. lineata is more likely to be in native brush and scrub areas (often in Oak areas), or in sand dune areas. Generally they favor different places, but it's not that unusual to find them together sometimes (they both are attracted to lights at night, which often brings them together).

Since they maintain their distinctions in habitat, even where they occur together, they seem to qualify as distinct species to me. However it's been stated anecdotally in literature that, apparently, in the laboratory barriers can break down and they are able to produce viable hybrid offspring (though I've never seen it properly documented, and I've not tried it myself). So, it's not unlikely that occasional intermediate hybrids might occur in nature too. It's one of those philosophical definition of a species questions - are these races of one species that stay separate only because of behavior, or are they different species?

Anyway, you may have both, possibly with some hybrids among them.

Even though the two seem to be totally distinct, most of the time, there are occasionally individuals that cause confusion. This one actually looks like exactly what you think it is. However, it's the other one that has me wondering. Did you take pictures of more of them? Also, where were they taken (location, habitat)?

Moved from Bird Grasshoppers.

Moved from ID Request.