Larry Moyer, Jr.,, of Allentown, Pa., for his question:

Where is the 17‑year locust for 16 years?

A locust is a relative of the grasshopper. He has a pair of powerful jumping legs and a pair of back wings that open out like gauzy fans. The insect we call the 17‑year locust is not really a locust at all. He is a cicada. He is a great nuisance to orchards and nurseries. But this fact should not stop us from admiring his life cycle as one of the great wonders of nature.

The great majority of insects enjoy life for but a year. The cicada lives for from four to 20 years, depending upon its type.. The 17‑year cicada has earned a bad name for himself in certain areas along the eastern seaboard. Even so, he is seen and heard for only one week of his 17‑year life, his last week. Daring this time, countless hordes of cicadas take t o the air.

Actually, this is a coming‑out party. The males and females mate and the females lay their eggs. The female cicada is fitted with a stiff spike which she pokes into a twig near the end of a branch. She places her eggs into the hole. Then she walks a little further from the end of the twig and pierces more holes. Maybe she hopes the twig will fall to the ground, carrying her precious eggs with it. Sometimes it does. In any case, the Mama Cicada has destroyed the twig. Later in the summer you will see it, hanging limply with its leaves dead and brown.

The eggs hatch in a few days. The youngsters are nymphs, small wingless copies of their parents. The little grubs jump or fall to the ground. They are fitted with sucking beaks and a pair of shovel‑like front legs. They start out at once to dig themselves underground. Down there they dig tunnels until they find themselves a juicy root. Then they settle down to food, moving from root to root.

The 17‑year cicada lives underground for almost his entire life. We cannot see or hear him, we do not even know he is there. However, he may be draining the sap and weakening our trees and shrubs. During his years below ground he grows. He does this by molting his outer skin. His new skin is soft and elastic at firs‑t. It stretches to fit his larger body and hardens in a few hours.

 The cicada nymph reaches his final molting stage 17 years after his birth, He is now an inch long and he has a pair of useless wing pads. The time has come to emerge. He crawls out of the ground and. part way up a tree. At the same time, thousands of his relatives are also emerging.

The weary nymph clings to the tree with his strong front paws. Then the miracle begins to happen. The tired skin splits down the back, and out struggles a pale ghostly creature; Gradually its crumpled wings become firm and gauzy. The pale insect takes on vivid color. In a few hours, countless hordos of cicadas are ready to stage their busy, noisy coming­ out party.