This has had a most important effect on the development in recent years of morphological anatomy.
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.
At the present time some objection is being taken to this purely morphological conception of the body and its parts as being too abstract.
Divergent views have been held as to the morphological significance of the pneumatophore.