Translation:A lot of small insects are crawling onto the wall: bees, flies, ants and butterflies.
and should be correct. Also, it is confusing when you want "on" or "onto" sometimes both should be correct.
Another mile long sentence that does not reflect reality. It is like a bunch of words written at random.
A lot of small insects: bees, flies, ants and butterflies. are crawling onto the wall was rejected and is in fact a more correct translation than yours