Complex sentence: Pruinescence, or pruinosity, is a "bloom" caused by pigment on top of an insect's cuticle that covers up the underlying coloration, giving a dusty or frosted appearance.
Split into simpler sentences: Pruinescence, or pruinosity, is a dusty looking coating on top of a surface. In insects, a "bloom" caused by pigment on top of an insect's cuticle that covers up the underlying coloration, giving a dusty or frosted appearance.