Synonyms and other taxonomic changes
Trimerotropis salina McNeill, 1901, described from Lincoln, Nebraska
Trimerotropis pallidipennis ssp. salina (McNeill) Hebard, 1928
? Trimerotropis schaefferi Caudell, 1904, described from Topo, nr. Brownsville, Texas
Explanation of Names
Is similar to and closely related to T. pallidipennis, which has caused confusion in the literature both as to where it is found, and as to how to define it. Generally it is considered to range north into Canada, but in his 1984 book, Otte considered all material north from South Dakota northward to be referable to T. diversellus, a related smaller species described from a different habitat in the Yellowstone area. In 1985 Vickery and Kevan recognized T. diversellus in the original restricted sense, and recognized T. salina as the wide-ranging species of the plains and prairies. Habitat should prove useful in sorting them out, but this information is often not recorded with museum specimens. Photographers and naturalists can be a big help in sorting out which species is where. As it is, northern Great Plains specimens "look" more like T. salina, but in reality the picture there may be more complicated than any publication has indicated.
The name T. schaefferi has been given to specimens from along the Gulf Coast in Texas, and is usually listed as a distinct species. T. schaefferi seems to represent merely an optimum larger than average expression of T. salina, with the tegminal cross bands more contrasting than average, and with the dark cross band of the hind wing wider than average. It seems likely that it is not a distinct species at all.
Size
males 23 - 45 mm
females 32 - 56 mm
largest specimens in s.e. Colorado and w. Kansas; smallest in s. Canada, Oregon, and n. California.
Identification
Very closely related and similar to Trimerotropis pallidipennis, but differs in hind wings proportionately wider and shorter, with usually much wider and differently shaped dark cross band (east of Rockies), or with the band usually fainter and less developed (Great Basin); with the yellow color of of the wing usually paler and less transparent, sometimes nearly white; proportions of body slightly more "stocky" with head proportionately somewhat larger; often with yellow on head and pronotum, especially below; habitat and behavior are different. This species is usually strictly limited to its small alkaline habitats, and while very active and difficult to approach, it usually makes shorter and less direct flights than T. pallidipennis, and will usually circle back to it's prefered habitat. It produces a similar relatively high-pitched interrupted buzzing when it flies.
T. saxatilis is also very similar, but averages smaller than T. salina when from the same area; with the dark wing band usually narrower and more irregular in shape, curving around the outer edge of the wing not so far. It occurs on rock outcroppings. T. diversellus is very like T. saxatilis, and may be the same thing from further west.
T. pseudofasciata is also extremely similar, and can be easily confused with T. salina in the Great Basin region where usually both have little or no dark band across the hind wing. They may sometimes be found together, they sound similar, and they behave in very similar fashion. However, the wings and hind tibiae of T. pseudofasciata are usually bluish (wings are never yellowish, though hind tibiae may be). Also, the crest of the pronotum is much more prominent and strongly bilobed toward the front, and there is sometimes a tooth at the lower rear angle of the lateral lobes of the pronotum.
T. huroniana is very closely related as well, but is found along the northern shores of the Great Lakes further to the east, and has wings more like those of T. pallidipennis.
On the Great Plains T. latifasciata can look similar, but is usually noisier and more powerful in flight (producing a louder, deeper, harsher sound); the coloring is often, but not always browner, and the hind tibiae and inner hind femur are red.
Range
In it's typical form with a wide wing band, found east of the Continental Divide on the Great Plains and western Prairies from Alberta to Manitoba and Minnesota southward to Texas and New Mexico, and perhaps into northern Mexico. (Or, according to Otte - 1984 - perhaps only south from Nebraska and Wyoming). In the Rio Grande drainage in s. Colorado and n. New Mexico, the wing band becomes narrower, but otherwise the insects are the same.
Populations usually with the wing band reduced or absent occur in the Great Basin between the Sierra Nevada and Rockies and from Oregon and probably Idaho to southern Nevada and southeastern California. They may represent a distinct species, but probably not.
There seems to be a large break in the distribution in the region of the Colorado Plateaus and Wyoming Basin, but the species may be present in those areas, simply having been confused with T. pallidipennis and/or T. diversellus.
Habitat
Usually barren salt or alkali encrusted flats, lake margins, seeps, etc. often where water sits temporarily, where the ground is muddy, but where surface crust is dry and cracked most of the time. Often associated with plants such as Iodine Bush, Pickle Weed, Salt Grass, Alkali Sacaton, Greasewood, etc.
Life Cycle
Overwinters as eggs. Adults mostly about June or July to early autumn.
