Well, OK, this grumble is not made any easier by the fact there is a daddy long legs spider and there is the crane fly, which flies, is not a spider and is also called a daddy long legs.
I only discovered this relatively recently, having spent my life knowing crane flies as "daddy longlegses", and spiders as, well, spiders (as in "tiny little spider", "big hairy spider", "evil jumping spider", "spherical spider of uniform density" and so on).
I get the impression that leftpondians never use "daddy longlegs" for anything other than the spiders, which adds to the confusion.
On a related note: Wood lice.