Insect Order Siphunculata - sucking lice
The Siphunculata are described as wingless (Apterous), hemimetabolous (having a simple metamorphosis i.e. no pupa) ectoparsites (living on the outside of their hosts) of mammals, there are about 300 described species of which 24 are found in Britain. They have reduced or absent compound eyes, no ocelli and no cerci. The mouthparts are adapted for sucking and retractable into a special cavity in the head when not being used. They are dorsoventrally flattened with strengthened legs which have large single claws and only a single tarsal segment as part of their special adaptation to clinging on.