Re: Is there a Daddy Long Legs lookalike in Iowa that can bite humans?

There are two different groups of arachnids that are called 
daddy-long-legs.  These are the "true" daddy-long-legs, or harvestmen, in 
the arachnid order Opiliones (or Phalangida) and the daddy-long-legs 
spiders in the arachnid order Araneae (spiders), family Pholcidae.  
Pholcids have venom glands while true daddy-long-legs do not.   Thus it is 
possible to be bitten by a daddy-long-legs spider, but not by a 
daddy-long-legs.   Generally, even this does not occur because 
daddy-long-legs spiders have very small fangs.

References:  

Levi, H. W., and L. R. Levi. 1968.  Spiders and their kin.  Golden Press, 
New York.