How do I generate a phylometric tree given species names?
Biopython may have a module for this. I know it can parses phyloxml files and render a tree. You can query the ncbi database for the xml files. Here is some sample code that will render an ascii tree given a phyloxml file...

from Bio import Phylo
tree = Phylo.read("examplephylo.xml", "phyloxml")
Phylo.drawascii(tree)


There is also support for drawing more graphically rich trees using matplotlib. There is a .pdf book for Biopython that you can download from this url http://biopython.org/DIST/docs/tutorial/Tutorial.pdf

Hope that helps