dimorphism : Idioms & Phrases
Seasonal dimorphism
(Zoöl.) , the condition of having two distinct varieties which appear at different seasons, as certain species of butterflies in which the spring brood differs from the summer or autumnal brood.
Webster 1913
Sexual dimorphism
(Biol.) , the condition of having one of the sexes existing in two forms, or varieties, differing in color, size, etc., as in many species of butterflies which have two kinds of females.
