Culex mosquito. Light micrograph of an unidentified mosquito (Culex sp.). Mosquitoes belong to the family known as Culicidae (order Diptera) which includes about 1500 species. Only the female mosquitoes bite. They use a piercing proboscis (upper right) which consists of a bundle of no less than six stylets. At the tip of the proboscis blood is mixed with the saliva which prevents clotting and hence the obstruction of the narrow food channel within the proboscis. Culex mosquitoes inhabit urban or rural areas and usually bite in the evening or at night. They can transmit the diseases encephalitis and filariasis. Magnification: x11 at 6x7cm size.