May use hairs to increase their surface area or wax to make themselves more water repellent. The only invertebrates and the first animal group able to fly. The first flying insects moved their wings by direct muscle attachment. Direct muscle attachment is the primitive state. Direct muscle - ex. human arm.
Direct muscle is attached to arm bone and pulls directly on the bone.
Indirect muscles are more efficient and capable of a higher wing beat frequency. Insect veins are apparent on most insect wings. Veins serve two purposes.