Synonyms and other taxonomic changes
Trimerotropis fratercula McNeill, 1901, from Pine Bluffs, Wyoming
Pseudotrimerotropis fratercula (McNeill) Kirby, 1910
Identical to Trimerotropis cyaneipennis, except wings are yellow (sometimes a bit greenish) and hind tibiae may be brownish, yellow, green, or to the south in Colorado and northern New Mexico blue (normally blue in T. cyaneipennis)
T. sparsa can also be similar in w. Nebraska, ne. Wyoming, w. South Dakota, near Pueblo, Colorado, and north of Santa Fe, New Mexico. It is usually larger (especially southward) with a plainer pattern and longer wings (hind wings usually narrower as well). The dark band on the hind wings is usually faint or absent. The habitat is usually more open and eroded areas. T. sparsa usually has blue wings, but in these areas they can vary to green or yellow. Hind tibiae are never blue.
T. verruculata usually has longer and even wider wings, with the outer part (beyond the band) usually clouded or black (usually mostly clear in T. fratercula). It is found usually at higher elevations in wooded areas (but they sometimes occur together), and it is usually much darker with dark brownish to black (sometimes blue or purplish) hind tibiae. Rare individuals in areas of contact appear to be hybrids.
T. inyo (greenish yellow wings) and T. bernardi (yellow wings) in southern California are similar, but are separated from T. fratercula by great distance. Both are in the mountains of southern California.
These species, along with other close relatives are very close to Circotettix, and cytological evidence supports this. They probably should not be placed in Trimerotropis, but it will take time and more study to sort this complicated group of genera and species out more naturally. Otte's system is decidedly the best so far, but there are still unresolved issues as to what "species" belongs with what.
northern New Mexico to se. Wyoming and sw. South Dakota on the east side of the Rockies.
Rock outcroppings, ledges, canyons, steep hot rocky slopes, etc. along east base of Rockies and northward out into the Great Plains as far east as the Nebraska Panhandle.
Species status for T. fratercula is highly questionable. It blends with T. cyaneipennis in northern and central New Mexico, and the two should probably be considered subspecies of a single species. There is a difference in chromosome number which is the same as the difference between T. verruculata verruculata and T. verruculata suffusa (which are closely related to this species). However, this number difference does not correlate well with the change-over in coloration. The higher chromosome number of T. fratercula is found well southward into the region of blue wings, and males with 23, 22, and 21 chromosomes can be found together in some New Mexico populations (matching females will have one more).
As a side note, the lower chromosome number found in much of the range of T. cyaneipennis is technically not really "different", because everything is still there. Two chromosomes in each set (there are two sets in each cell) have fused together to make one (so there appear to be two less chromosomes per cell). They still match the corresponding chromosomes in individuals with the higher number. The 22 chromosome individuals have the unfused pair in one set of chromosomes, and the fused chromosome in the other set, so they have the apparent intermediate total number of chromosomes.