Synonyms and other taxonomic changes
Trimerotropis Stål, 1873; type: Trimerotropis maritima (Harris)
Pseudotrimerotropis Rehn, 1902: type (by later designation - Kirby, 1910): Pseudotrimerotropis cincta (Thomas)
Identification
Mostly relatively slender, medium-sized (mostly between about 1 and 2 inches long). The pronotal ridge is cut twice, usually faint or entirely absent on the posterior half of the pronotum (metazona). The front wings have dark markings, usually dark cross bands that may be clear and well-defined or made of congregations of small irregular dark spots. Hind wings with the basal portion colored yellow, green, or blue (never reddish colors), and usually with a dark cross band that usually has a spur that extends toward the base of the wing near the front edge. Hind femora usually with at least faint diagonal crossbands externally, and perpendicular light and dark banding on the inside (in some mostly light or dark). Hind tibia varies in color with the species (brownish, blue, green, yellow, orange, red, or rarely purplish, and can be useful for species identification.
(1)
Circotettix species have wider (often very long) wings; hind wings with the outer edge often a bit undulate, and with at least some of the radial veins very strongly thickened. Hind tibiae are never reddish.
Spharagemon, which mostly have the top of the pronotum less flat (more roof-like) with the median ridge raised more (often forming a crest) that is cut once (sometimes notched a second time, but mostly not). Dissosteira differs similarly, and all have distinctly different wing coloration (one rose-colored).
Conozoa are best distinguished by comparing individual species, since most cannot be reliably separated from Trimerotropis (some have a once cut pronotal ridge). They run smaller and more slender on average, with the dark cross bands of the tegmina (front wings) usually not crossing the top when folded over back. The rear lower angle of the sides of the pronotum are most often produced downward into a sharp angle or tooth. A combination that is distinctive, but not universal, and not unique.
Microtes species are very limited in distribution (near the Pacific Coast), and average smaller, and seem a bit stockier (mostly due to shorter wings).
Remarks
As currently defined, this is the largest American genus of Band-wing Grasshoppers, and there is a wide range of variation in appearance, size, and behavior. They can be found in nearly all habitats that are sunny, relatively dry, and have bare ground or rocks exposed. There are few species in the East and many in the West. They are very closely related to a few other genera (most notably Circotettix, Spharagemon, Conozoa and Microtes, and it is likely that limits of the genus will be redefined as more is learned about how species are related to one another.
Apparently all species can produce noise during flight (crepitation), and often the pattern and nature of the sound produced can help identify species.
Based on a number of traits (including characters of chromosomes, morphology, coloration, behavior and sound, ability to hybridize, etc.), most species can be arranged into groups of close relatives. It is quite likely that in the near future, some of these groups will be arranged into separate genera, but for now they are all called Trimerotropis.
Those very close to Spharagemon include: T. pistrinaria, modesta, tolteca, and probably T. inconspicua. Spharagemon campestris and perhaps Spharagemon bunites belong with these; or, perhaps all of these should be included within Spharagemon. In flight these produce a loud and moderately harsh continuous buzz (unreported for S. bunites), and tend to fly in a relatively straight or evenly curved path. All of these normally have orange to red hind tibiae (rarely yellow, and with the exception S. bunites with blue).
T. latifasciata and T. melanoptera are closely related and fairly similar to both the previous and next groups. In flight these produce a loud and moderately harsh interrupted buzz, and they tend to turn and zig-zag in a low rapid flight. The unnamed "species B" listed on BugGuide probably is most closely related to these, but has a less loud and harsh crepitation. All three have orange to red hind tibiae.
Those most closely related to the type species of Trimerotropis (T. maritima), are: T. agrestis, californica, pacifica, titusi, and topanga,. In flight these produce a loud and moderately harsh continuous buzz, and tend to fly in a relatively straight or evenly curved path. In restricted habitats they tend to fly shorter distances or turn back to near where they started from. All of these have yellow to red (mostly the later) hind tibiae, except for T. topanga which has blue.
T. albescens, arenacea, & whitei are very similar to one another, and perhaps closely related to the previous group. These produce a moderately loud and harsh buzz, but (perhaps due to small size) not as loud as the previous group, similar to previous in flight pattern. These have blue, blue to yellow, and yellow to red hind tibiae respectively, and seem to form a cline of continuous variation from west to east (perhaps all one species).
Forming a seemingly close knit group and perhaps related to Conozoa are: T. cincta, fontana, infantilis, koebelei, occidentaloides, santabarbara and perhaps T. bifasciata & T. occulens. These produce a rapid, not harsh buzz or interrupted buzz in flight, they often tend to make unexpected, often upward turns in flight, and will often fly into or through brush. These all have blue hind tibiae, usually black at the very base with a pale ring near the base, and often dark at the tip too.
All of those species listed above have or are suspected of having structurally typical chromosomes, basically as in most other grasshoppers (? except perhaps "Spharagemon" bunites?), and also share a typical chromosome number of 2n=23 (males) or 2n=24 (females). They are likely (all or at least most) more closely related to Spharagemon, Conozoa, and perhaps Microtes than even to the species listed below.
All of those species listed below, where known so far, share certain modifications of chromosomes with Circotettix, and as in that genus, many (not all) have a reduced chromsome number due to a fusion of two chromosomes of each set into one, resulting in 2n=21 (males) or 2n=22 (females). Thus, those below are probably (all or at least most) very closely related to one another and to Circotettix.
Those closely akin to Circotettix seem to include: T. arizonensis, bernardi, cyaneipennis, fratercula, gracilis, leucophaea, sparsa, verruculatus, and the unnamed "species A". These crepitate with a moderately loud and harsh crackling sound made up of rapid separate bursts of two or three snapping sounds each (except T. gracilis which ticks with the same basic pattern, but only one snap per "burst" or "pulse"). Most tend to have a rather direct flight when startled, but when not disturbed many bounce and zig-zag around when they fly. Hind tibiae in this group vary from species to species and often individual to individual, but are never reddish, and often are blue.
T. inyo, lauta, occidentalis, thalassica, "Microtes" helferi, and maybe "Spharagemon bunites" are somewhat similar, and perhaps closely related to the previous. They may together form a closely knit group, or not. Several of them are poorly studied. They apparently all produce a less harsh more rapid interrupted "buzz" or "crackle" (unreported in S. bunites). Mostly, these have blue hind tibiae, never reddish.
Those close to T. pallidipennis include: T. huroniana, pseudofasciata, salina, saxatilis, & schaefferi. In flight they produce a rather loud, rapid, not particularly harsh interrupted buzz, with the pulses varying from three or four to several ticks each. Those from restricted habitats tend to not fly long distances and often turn back on their previous path. Even so, it is usually a rapid direct flight. Where the habitat is extensive they tend to have a rapid long direct flight. Hind tibiae are yellow (sometimes brownish), except in [i]T. pseudofasciata, in which they are usually grayish or brownish to most often blue (rarely yellowish).
