Independent studies fall under the category of Directed Studies in the catalog. The language you are looking for is this:
Directed Study (department alpha) 170, 270, 370, 470, 670
This provides students the opportunity to gain experience with learning on a one-to-one basis. Prerequisite: for 370, 470, and 670, previous coursework or experience in the field to be studied. 2–4 credits. Credit/No Credit grading only.