These highly osculating curves were studied, in particular by V.I. Arnol'd. One of the important refferencesreferences will be:
Topological invariants of plane curves and caustics. Dean Jacqueline B. Lewis Memorial Lectures presented at Rutgers University, New Brunswick, New Jersey. University Lecture Series, 5. American Mathematical Society, Providence, RI, 1994.
More precisely, what was studdiedstudied are the points of the curve, where the level of itits tangency with (say) conics is higher than expected. I guess these are exactly the points that (using your terminology) separate the elliptic part of the curve formfrom the hyperbolic part.
The key words for thesethis research are Extactic points (therminologyterminology proposed by D. EsenbudEisenbud). Using google scholar you can find a complete text of Arnol'd, called:
Remarks on the extatic points of plane curves, V.I. Arnold - The Gelfand Mathematical Seminars, 1993-1995.
TheseThis article contains some genearlisationsgeneralisations of the four vertex theorem. http://en.wikipedia.org/wiki/Four-vertex_theorem
One more nice refferencereference is a paper of Tabachnikov and Timorin. http://arxiv.org/PS_cache/math/pdf/0602/0602317v2.pdfhttps://arxiv.org/abs/math/0602317