From the Caltech website:
[You should really improve your researching skills…]
“Caltech is not listed as one of my IDOC schools.
Caltech works with IDOC differently than most other schools. Caltech will not request your information from IDOC until after you have been accepted for admission. This means that Caltech will not be present on your list of schools on the IDOC website, and you will not see any Caltech-specific forms in your required document list. Please review our list of required documents carefully and be prepared to submit them all to IDOC, even if IDOC does not appear to be requesting some of them. IDOC will process them and keep them on file; once you are admitted, your Caltech-specific documents will be delivered to us.”