Aphid

Aphids, the vampires of the plant kingdom, are members of the order Hemiptera (the true bugs) in the class Insecta. In common with other hemipterans, aphids are equipped with highly modified mouthparts that permit the injection of salivary juices and the siphoning-off, in this case, of phloemic plant juices. Analogous to the anti-clotting substances of mosquitoes, leeches, and many endoparasites, aphid saliva contains a compound that prevents the normal healing of a plant wound until the insect has feasted. Two tubes or cornicles, resembling the dual exhausts of an automobile, excrete a sugary waste product known as honeydew.