Where do the insects "toe bitters" come from, the ones that end up in the swimming pool?

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They are a native species of North America. I had never heard of them so was curious and found the website below, that tells the scientific name. Maybe if you alter the lighting and surroundings of the pool that attract prey you could control them.. or if it's a small pool with out chemicals I'd try just a small amount of bleach. (Unless you are an insect collector..in which case I'd find a jar, pin and mounting board)