A couple in Alabama made a claim on their homeowner’s insurance because their home was “infested” with brown recluse spiders.* The insurance company denied coverage because the policy excluded loss due to “birds, vermin, rodents, or insects”. The couple sued, arguing that spiders aren’t insects – and lost, and then lost again on appeal. So, legally, it seems that (at least in the jurisdiction of the 11th Circuit, viz. , Alabama, Florida, and Georgia**), spiders are insects.
Words fail me. I would never call a spider an insect!