Mosquitoes are small insects. That always makes us feel annoyed when they see or hear it fly around because we know that if a mosquito bites. There are already itching. We might as Malaria, Dengue fever, Yellow fever, and encephalitis. Or even Zika virus disease.The world has more than 3000 species of mosquitoes, the mosquitoes do not carry any disease, and there are about 100 species that can kill people. Biologists have found that mosquitoes that bite people, is the only female mosquitoes. Because it needs the blood guard to lay eggs. At bite, it will use the beak pointed like needles penetrate into the blood vessels under the skin and release the saliva came out to prevent blood coagulation and suction it if the mosquito carries the disease. The germs in saliva, it enters the body, most people there are chemicals in saliva will make the person feel itchy mosquito bites until some people have allergies or feel out of breath, until the dark page, etc.