palp

This form is retained, with little alteration in some adult Copepoda, where the biramous “palp” still aids in locomotion.

A palp sprouts on the mandible and the median eye disappears.

A second ramus, the “exopodite,” often is also retained in the form of a palp or feeler.

In bugs and aphids the lacinia is a slender needle-like piercer (fig. 2, III), while the palp is wanting.