Ricki Green. Age 12, Of Newport News, Va., for his question:      

What makes a mosquito bite itch?     

When a mosquito attacks, you become a blood donor. The pesky insect dines on a sip of your blood. You would think this enough injury, but not at all. The mosquito injects your flesh with an itchy chemical., and the bumpy wound will hurt for days.
Squadrons of mosquitoes arrive in early summer. They are out in force in the woods and around our swimming pools. They battle for our picnic grounds and even challenge our rights to a quiet evening on the porch. It is wise to protect ourselves     From these blood thirsty creatures. Their so called bites., as all of us know, are very annoying, and the wounds may lead to more serious trouble. A so called mosquito bite is actually a piercing stab to reach a small blood Vessel under the skin. A squirt of saliva is then injected into the wound. This watery liquid with its dissolved chemicals thins the blood and prevents it from clotting. The mosquito must take her food in liquid form. She syphons up your blood from the stab and flies away.     This part of the operation is usually painless. The mosquito's beak is a bag of delicate surgical tools, and she works with a feathery light touch. Later, the wound begins to swell and itch, and the irritating bump is caused by the chemicals that the mosquito injected into the wound to prevent the blood from clotting before she had finished sipping her dinner.
As she feeds, the mosquito draws up blood fresh tissue around the wound, and this blood has been injected with the itching chemicals. If her meal is interrupted,, she flies off leaving most of these chemicals in your flesh. For this reason, it is not wise to swat her while she is feeding. Wait and let her syphon off as much chemically  saturated blood as possible.     Some mosquitoes inject deadly germs with their saliva, and many others carry milder microbes. It is always a temptation to scratch the irritating bump, but scratches may tear the skin, leaving it open to infections. A so called mosquito bite should be treated with a swab, a dab or a spray of medication. Choose one that contains ingredients to ease the itching and other ingredients to cut down the danger of infection.     Only the female mosquito can cause a bite; the male is quite harmless. And there is a way to tell which is which. Mrs. Mosquito zooms around with a whining Buzz; her husband flies on quiet wings. His beak is not strong enough to pierce human skin, and since all adult mosquitoes must dine on liquids, he must be content with the juices from fruit and tender plants.