The standing of the Trichoptera in a position almost ancestral to the Lepidoptera is one of the assured results of recent morphological study, the mobile mandibulate pupa and the imperfectly suctorial maxillae of the Trichoptera reappearing in the lowest families of the Lepidoptera.
Considering the wide differences between the two groups in the size and external characters, and in the mode of life, including the mode of feeding, it is indeed surprising that in every important organ the two groups should show a fundamental morphological identity.
Divergent views have been held as to the morphological significance of the pneumatophore.
Rosenkranz, who in his work Hegel's Naturphilosophie seeks to develop Hegel's idea of an earthorganism in the light of modern science, recognizing in crystallization the morphological element.
Evolution, or development, is, in fact, at present employed in biology as a general name for the history of the steps by which any living being has acquired the morphological and the physiological characters which distinguish it.