Undulant-Winged Grasshopper

Found west from the Rocky Mountains. Hind wings usually greenish to blue (yellowest in the north, bluest in the south), and hind tibiae usually blue (sometimes greenish, or grayish). Dark wing band usually faint to absent (when present, usually closer to end of wing than in C. rabula . Differs from C. shastanus (with which it intergrades) by presence of a vein (usually designated as the anterior branch of 2Aa) free from vein 2A (2nd annal vein). In C. shastanus the wings are usually yellow (also green to blue where it meets C. undulatus in the Sierra Nevada); the anterior branch of 2Aa is usually fused with vein 2A, and the dark wing band is usually present and fairly well-deveoloped. The blue specimen here shows possible influence from C. shastanus , and the yellow one is an example of that species with the veins completely fused, with just the very base of 2Aa visible, where it crosses and joins. C. rabula is found mostly further east in the Rocky Mountains and western Great Plains, has yellow wings, usually browinish to yellow hind tibiae, and the wing band is more in the middle of the wing and usually well-developed (but it varies with elevation and location). C. stenometopus is mostly found further west in northern California, and is colored similarly to C. rabula . C. coconino and C. crotalum are more like C. rabula in coloring (except they have blue hind tibiae). However, with wings closed, C. crotalum is nearly identical to C. undulatus in appearance. Neither is found in the same regions as C. undulatus . Similar Trimerotropis species have wings shaped differently and the annal (= radial) veins never so prominently thickened. This species is one of those that is hard to ignore when you are in the same area as it on a warm summer day. It crepitates loudly when it flies (making a loud interrupted and harsh buzzing that is punctuated by even louder snapping or popping soundns). The males perform flight displays, during which they rise vertically high into the air and hover or bob up and down as they produce their crackling song. Females are similarly loud, but do not often participate in the aerial display. Often its steep rocky habitats tend to accentuate the noise by echoing it back at the listener.