Question

In which part of the alimentary canal of cockroach is the invagination of the cuticle found
A. Anterior part
B. In the mid part
C. In the posterior part
D. Both in the anterior and posterior part

Answer 1

Hint:The major part of the integument in arthropods is the cuticle that includes most of the exoskeleton in the insects like Myriapoda, Arachnida, and Crustacea.

Complete answer: A single layer of the ectodermal epithelium is the product formed by the integument of the external skin/shell in arthropods. This layer is attached to the non-cellular internal membrane that is the distal surface of the deepest layer in the integument. The basement membrane is called the non-cellular membrane. Rough cuticle and flexible chitin are produced by the basement membrane on the layer of epithelium. Flexibility is necessary so that body parts of the insects retain the liquids from joints between the exoskeleton rigid parts that are functioned by the major structural part called the flexible and thin chitin. In other parts of the cuticle, the function of the integument demands more rigid materials, such as armored regions or the biting parts of the jaws, or where the exoskeleton forms the tubular limbs of most Arthropods. For attaining the type of rigidity the outer layer of the chitin cuticle is impregnated, thickened, and fusion brittle materials like the sclerotized proteins and calcite. Procuticle is the main chitinous layer of the cuticle. In cockroaches, the cuticle is present in both the anterior and posterior regions of the alimentary canal.
Hence, the correct option is (D) Both in the anterior and posterior part.

Note: The procuticle in most land Arthropoda, particularly insects, is covered externally with a thin, waxy, water-resistant outer layer containing no chitin. Epicuticle is the outer layer and much thinner than the procuticle. The chitinous procuticle is formed of an outer exocuticle and the inner endocuticle, and between the exocuticle and endocuticle, there may be another layer called meso cuticle which has distinctive staining properties.