“Is comprised of” is one of the worst pretentiousisms out there, and one that bugs me the most. Don’t ever say it!
Here’s the rule:
When you’re talking about a whole thing and its parts, compose goes from the parts to the whole, and comprise goes from the whole to its parts.
Here’s a guy who got it right:
OVER 5,000 YEARS AGO IN what is today Slovakia, a Neolithic community erected a new building. It wasn’t the first “longhouse” in Vráble, an early town comprising about 100 buildings in all.
I mentioned this topic before. For more examples, use the search box in the upper right.
Here’s a picture:
PS—Just ran into another correct usage:
Another example is Isabel de Olvera, a free woman of African descent, who in 1600 went on an expedition to New Spain (a region comprising present-day New Mexico, Arizona, Florida and other parts of North and South America), in search of trade goods and new places to settle.