Spider veins are tiny, thin veins that can be seen very close to the skinâs surface. They look like red, blue, or green spider webs just beneath the skin. Sometimes they are also described as looking like marble. Spider veins are caused by a backup of blood. These become nonfunctional, âdead-endâ veins.
While the fairy fly is the worldâs smallest insect, there a few runners up! For example, the feather wing beetle is only .25 millimeters long. Some scientists think these beetles may even be smaller than fairy flies, but for now, the fairy fly is considered by many to be the âsmallest insect!â.
Threadworms (Enterobius vermicularis) are small worm parasites that infect the intestines of humans. Threadworms, sometimes known as pinworms, are white and look like a small piece of thread. The adult female worm can be 8-13mm long, and the male worm 2-5mm long. Adult worms live for up to six weeks.