Which common name is considered biologically inaccurate due to confusing the insect with an arachnid?

Answer

Water spider

The term water spider is misleading as these organisms are insects (Hemiptera), not spiders, which belong to the class Arachnida.

Which common name is considered biologically inaccurate due to confusing the insect with an arachnid?
nameanimalinsectwaterbug