Traits

A popular feature on insectoid leeches, the spider jaw features an advanced claw-tipped feeler that has developed muscles and can be moved about or used to help the leech feed.
The feelers can originate outside or inside the mouth.

These feelers are generally very receptive to touch, and often feature a claw or pointed end as their main use is for grabbing and directing things into the leech's mouth.  Claws can be filed down for safety, but the leech must first be trained to be comfortable with this procedure - since the claws are in such close proximity to the mouth it can be easy to receive a bite from a fussy or upset leech.  

Note: It may be accompanied by any type of teeth.