Polygonia comma and by the row of pale submarginal spots on the hindwing upperside, which tend to be separate and surrounded by dark shading in comma, but are larger and tend to run together into a pale band in "P. satyrus". Polygonia comma Polygonia comma, the eastern comma, is a North American butterfly in the family Nymphalidae, subfamily Nymphalinae. This butterfly is seasonally variable. The upperside of the summer form's hindwings are all black, whereas the winter forms hindwings are reddish orange. The underside of both forms is striped with dark and light brown. There is a silvery comma mark in the
Comma category difference between the two notions is that a natural transformation is a particular collection of morphisms of type of the form formula_182, while objects of the comma category contains "all" morphisms of type of such form. A functor to the comma category selects that particular collection of morphisms. This is described succinctly by an observation by Huq that a natural transformation formula_183, with formula_184, corresponds to a functor formula_185 which maps each object formula_8 to formula_187 and maps each morphism formula_188 to formula_16. This is a bijective correspondence between natural transformations formula_181 and functors formula_185 which are sections of both