The flat white wings of this long-legged creature, vibrating rapidly in the air, make what everyone will agree is the most annoying sound in the world. They make the mosquitos' hum. The cigar-shaped abdomen is striped like a convict's jacket. As a boy there was to me a peculiar fascination in watching that abdomen pinken and turn red along its sides as it filled with blood sucked from my hand. The large eyes compose almost the entire head of a mosquito and in some species they are of an emerald green hue. Straight out in front, close together, curved downward at the tip, are two antennæ furnished with delicate hairs arranged like a bottle brush. With these the creature hears the love hum of its mate and probably scents also the neighborhood of any warm-blooded animal. Were this a male, instead of a female, these hairs would be much longer and there would be many more of them--they are the smelling organs of the creature and the hearing organs, too, being set into vibration by sound waves of a certain rate. It is important to remember this, for only the females are bloodthirsty. The long, slender proboscis projecting from the head, downward, is furnished with sharp, piercing stylets which, by working up and down, cut their way through the skin. Ordinarily the males and females both are content with sap of plants and fruits as their food, and blood does not seem to be a necessary part of their diet. It is curious that what is supposed to be merely an acquired habit of the female only, of an insignificant little fly, should mean so much to mankind. Just why a mosquito bite is poisonous is still a matter of question--the suggestion has been made that since both male and female really live on plants, the fluid which the female injects is for the purpose of preventing the plant juice from coagulating during the process of sucking and merely happens to be irritating to warm-blooded animals. There are three hundred different species of these creatures already described and fortunately this one, a species of culex, is not responsible, so far as known, for the carrying of any human disease. [Illustration] ONE OF THE HARMLESS ANOPHELES MOSQUITOS (_Anopheles punctipennis_, Say) The malarial mosquito, so called, has spotted wings, but otherwise it looks quite like this harmless form from Maryland. This whole tribe of Anopheles differs from the Culex in the length of its mouth feelers, which project from the base of the proboscis and appear in the photograph almost as long as the proboscis itself, whereas in a photograph of the Culex it would appear so short as to seem merely a thickening of the base of the proboscis. The wildest fancy of the Arabian story-teller is lacking in imagination compared with the story which the facts of modern science have woven about these tiny representatives of the fly family.