If I use a scientific name (Python regius) in a phrase that is already in italics, should the scientific name then be written normally or underlined? Does anybody know the rule?
Underlines are only used to indicate hyperlinks; they should not be used for emphasis.
When you have a block of italicized text, and you have a phrase which would normally be italicized in book or roman text, make your italic phrase book.
The ball python, also known as Python regius, is a nonvenomous python species found in Africa. This is the smallest of the African pythons and is popular in the pet trade, largely due to its typically docile temperament.