According to Hinds they feed chiefly on the green tissues, which " are punctured by the piercing mouth-parts and the sap withdrawn by suction.
The structure of the mouth-parts is different from that seen in any other insects.
It is now held that the parasite enters the blood of man through the piercing mouth-parts at the time of biting.
The mouth parts are well developed, consisting of an upper lip, powerful mandibles, maxillae with three-jointed palpi, and a deeply quadrifid labium or lower lip with three-jointed labial palpi.
The term "biting-lice" is sometimes given to these parasites, in allusion to the mandibulate character of their mouth-parts, which serves to distinguish them at once from the true lice of the order Rhynchota in which the jaws are haustellate.
