Bernadette Keto, age 11, of Libertyville, Illinois, forher question:

What determines the size of a mosquito bite?

The so called bite is a stab wound and its size is determined by the pesky critter's jabber    which is minuscule. The painful bump that swells up around the tiny wound is caused by saliva that the mosquito injects into the flesh. The size of the bump is determined by how much damage this does to the living cells. Body chemistry varies slightly from person to person and some are more allergic to this mosquito saliva than others.

The tiny stab is made by the mosquito's beak, which is where her nose should be. This remarkable proboscis is six mini tools called stylets and when not in use, the tool kit is encased in a tubular bag of skin. When the stylets stab through the skin, her special saliva oozes down into the tissue. Its purpose is to prevent the blood from coagulating so that the insect can sip up her meal in liquid form. However, the saliva chemicals also resemble bee stings, which also harm some people more than others.