Python pip install fails: invalid command egg_info

I find that recently often when I try to install a Python package using pip, I get the error(s) below. I found a reference online that one has to use "python2 setup.py install" from the download directory, and indeed find that this will then work if I manually find and download the package (from pypi). But, I don't know where pip is downloading packages to, and/or why it is failing in this manner.

[katsuopy]

[*2014/04/29]