Yes, "Barea sp" should not be used. Using Barea as an example, the general situation is as follows. "Barea (genus)" is for records that we can't identify to species level, but believe they are a species of the Barea genus. There will often a a number of different species placed under that heading. "Barea undescribed species" is for a group of records we believe are all are the same species, but one that has not been described and given a name. When there is more than one such undescribed species in the same genus, we have to resort to artificial names like the longstanding and well known "Philobota undescribed species near arabella", or "Philobota mathematica group undescribed species", even "Proteuxoa provisional species 1" (and 2,3,4,5). There are many such undescribed species in the moths. I have in the past spent a fair bit of time regularising such names in different parts of the moth taxonomy, but new "Genus sp" keep being created.