Generally we are not allowed to put a tent taller than 10 tefachim inside of a succah. But can one use mosquito netting inside of a succah that would allow in light but not dangerous insects?
(As with any practical halachic question, please consult with your own rabbi.)
I. See אור יצחק by יצחק עבאדי here :
He allows such a netting.
II. A slightly different question is found here:
The question is dealing with an open area surrounded by buildings, the top of which is covered by bird-netting. The author is lenient, but it should be noted that he's dealing with a case where there's no other place to build the סוכה.