The BVD stands for Back Vertex Distance, this is a measurement that is included on any prescription where the sphere or cylinder powers are higher than + or - 5.00D and to a lesser extent some prescriptions where it is less than this power.
Winged Drone | Alate | Male Ant. Drones are the only male ants in a colony. They are born from un-fertilized eggs. Drones are not like typical ants. They donât do any work in their nests, and they look more like wasps than ants. They are reproductive winged ants and so are alates.
Carpenter ants are one of the largest of all ant species. Carpenter ants have polymorphic workers, meaning that ants within a single colony may vary in size. Adult carpenter ants can measure from 6 to 12 mm in length. Males, or winged swarmers, can measure up to 18 mm, while queens grow to 20 mm in length.Carpenter Ant Size.A mature colony usually contains around 3,000 adult ants, but some species have been known to contain up to 100,000 ants. Like other ant species, carpenter ants are social insects, and their colonies are composed of different castes.ales, or winged swarmers, can measure up to 18 mm, while queens grow to 20 mm in length. Carpenter Ant Size. A mature colony usually contains around 3,000 adult ants, but some species have been known to contain up to 100,000 ants.