How do armoured scale insects differ from soft scale insects?

Armoured scale insects (family Diaspididae) and soft scale insects (family Coccidae) are distinguished primarily by their physical structure and the nature of their protective coverings.

• Armoured Scales (Diaspididae): These insects are characterized by a firm, waxy covering that is separate from the insect's body. In females, the apical segments are fused to form a structure known as a pygidium. Additionally, adult females lack legs, possess rudimentary antennae, and have a one-segmented beak.1
• Soft Scales (Coccidae): These insects often have a tortoise-like appearance and are typically flattened and oval-shaped. Their exoskeleton may be hard, smooth, or covered in wax, but unlike armoured scales, this covering is not a separate entity from the body. Soft scales may retain legs, though they can be absent, and their antennae are either absent or significantly reduced. A key diagnostic feature is that the anus is covered by two dorsal plates.1

While armoured scales are defined by their distinct, detached protective cover, soft scales are generally more active throughout their life stages.213