An Electron Diffraction Study of the Crystalline Structure of the Lipids in the Pupal Exuviae of Calliphora Erythrocephala

Electron diffraction techniques have been extensively used for the direct crystallographic examination of thin films of fatty materials, but they have hitherto not been applied to the study of natural membranes. These techniques provide more information than diffraction of X-rays about the atomic and molecular organization of surface structures. X-ray diffraction methods have been used successfully by Fraenkel & Rudall (1940, 1947) for elucidating the molecular organization of the chitin and protein components of the bulk cuticle framework in blowfly larvae ; but the thin lipid-rich epicuticle constitutes a small proportion of the entire cuticle, and would not contribute effectively to the observed diffraction patterns.