The body wall of periplaneta  consists of

outer – cuticle ,                                                                                                                        middle – epidermis  and                                                                                                             inner – basement membrane.

1)   CUTICLE :-

The body of cockroach is covered by chitinous cuticle. It consists of  three layers , namely ,  an outer – epicuticle ,                                                                                middle –exocuticle  and                                                                                                            an inner – endocuticle.

I.  Epicuticle:

  1. This is a thin nonchitinous layer present on the entire body surface of three parts , they are     outer –lipoprotien cement layer ,                         middle – wax layer and                                                                                                 an inner – layer of polyphenols.
  2. It lacks chitin.

 II.  Exocuticle :

  1. It is the middlae layer of the cuticle. It forms sclerites.
  2. The  rigidness of the sclerites is due to the polymerization.
  3. The cuticle between the segments of the body and at the joints of appendages  is soft and flexible  due to the absens of the rigid exocuticle in it. But it has only epicuticle and endocuticle. This cuticle is called arthroidal membrane. It allows  the bending movements of the appendages at the joints.
  4. Exocuticle is pigmented.

III.  Endocuticle :-

  1. It is the inner layer of the cuticle.
  2.  It consists of several layers of chitin.
  3. Endocuticle does not undergo sclerotisation and is lysed just before each moulting or ecdysis.


  1. A layer of columnar epithelial cells called epidermis is present below the cuticle.
  2. The cells of epidermis are functionally and structurally different types. They are
    1. Columnar epidermal cells – these are glandular  and secrete the cuticle. Some of these cells secrete enzymes that lyse the endocuticle during moulting.
    2. Trichogen cells – form movable bristles .
    3. Tormogen cells – form the sockets in which the movable bristles are buried.
    4. Oenocutes – secrte the wax layer of the epicuticle . These are the sunken epidermal cells.


The basement  membrane consists of a thin layerof connective tissue and forms the inner most layer of the body wall.


About balarangaiahnarapuram

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