Complex sentence: The genus "Colletes" (or plasterer bees) is a very large group of ground-nesting bees within the bee family Colletidae, with over 450 species worldwide, primarily in the Northern Hemisphere.
Split into simpler sentences: The genus "Colletes" (plasterer bees) is a large group of ground-nesting bees of the family Colletidae. There are over 450 species worldwide, primarily in the Northern Hemisphere.