Determining whether or not crickets are harmful really depends on what you define harmful to be. There are three types of crickets commonly found in the United States: camel crickets, house crickets, and field crickets. All of these crickets have a mouth, and they can bite, but honestly, it's rare. They generally prefer to hop away. And, just in case you're wondering, no, they're not circling around to attack you from behind. Crickets have no interest in gnawing on your flesh. So, does that mean they're harmless? Not if you consider extreme mental duress harmless.
It's worse than your seven-year- old son practicing for recital so the answer to this question is, yes, crickets are harmful. After a weekend infestation you'll need to see a shrink for months. And, who knows if you'll ever be the same again. Okay. Maybe I'm exaggerating. But if you've ever had an infestation of crickets, you're nodding right now in agreement, aren't you? Three days of sleep deprivation sticks with you or his strings recital.