There are good biological reasons for keeping
T. custator and
T. pallidovirens as separate species although they are virtually indistinguishable morphologically. For the longest time, in the older literature, the common
Thyanta species (coast-to-coast distribution) was called
T. custator. Then Herb Ruckes revised the group and decided that the common species (coast-to-coast) was actually
T. pallidovirens, with
T. custator limited to Florida. He also divided
T. pallidovirens into three sub-species which he called
accera (with black spots on the abdomen, mainly midwestern and northern in range),
spinosa (with spinose humeral angles, mainly southwestern), and
pallidovirens, found on the west coast, which didn't have the ventral spots or the spiny angles. As with any subspecific characters, they tend to breakdown in the areas of transition. Dave Rider then reversed Ruckes and decided that the common coast-to-coast species was
T. custator, and would have done away with
T. pallidovirens as a synonym except for a study of the chromosomes by Ueshida at U. Berkeley. The California populations have 2n=16, whereas the midwestern population has 2n=14. So I basically follow Rider who kept the species names. If it's from California and doesn't have spines or spots on the abdomen I call it
pallidovirens. Everything else is
T. custator. (
D.B. Thomas's comment)