This package is not in PyPI. There is a page there, but the source code for some reason is somewhere else (this is the first time I saw it):
Ubuntu has a (possibly old) package:
$ sudo apt-get install python-pcapy
You can also create it from the source:
$ sudo pip install "http://corelabs.coresecurity.com/index.php?module=Wiki&action=attachment&type=tool&page=Pcapy&file=pcapy-0.10.8.tar.gz"
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