The answer to 15 down appears to be DANAID but there are 7 squares. Is there a variant of danaid with an E on the end or does one add an S to pluralise the word?
I have the same problem. The question is definitely a butterfly, not butterflies, which seems to rule out danaids. Also though danaine is the right length, it does not fit with 25 across. Danaide is a water wheel.