Mating in earthworm is a unique process, earthworm is a hermaphrodite organism. Breeding in earthworm takes place during rainy season and begins with copulation soon after maturation of the sperms.

The gametic exchange and the physiology reproduction during mating can described as below

(i) Earthworms are protandrous animal (i.e., maturation of sperm takes place much earlier then that of ova).

(ii) Mating process in earthworm occurs through cross-fertilisation.

(iii) The mating process involves exchange of sperms between the two worms.

(iv) Two individuals from adjacent burrows half emerge out and lie in contact with each other, and opposite gonadal opening exchange the packets of sperms called spermatophores.

(v) During the process, the skin encircling male pore, elevates a little to form a temporary papilla that fits like a penis into the opposite spermathecal pore to keep it open.

(vi) After filling of spermathecal, the copulating worm moves a bit to adjust another pair of spermathecae to face the male pores of the other. This is accomplished in about an hour's copulation.

(vii) Within the spermathecae, the sperms mostly remain in their diverticula and the ampulla is associated with the secretion of nutritive substances for the sperms.

(viii) The sperm and egg are passed into cocoon which is secreted by clitellar gland.

(ix) Fertilisation is therefore external and cross fertilisation.

The alimentary canal present in cockroach is divided into three regions that foregut, midgut and hindgut.

(i) Foregut includes mouth cavity, pharynx, oesophagus, crop and gizzard.

(ii) Mouth cavity is a small space, surrounded by mouth parts. Food is crushed and acted upon by the salivary secretion in mouth.

(iii) The mouth opens into a short tubular pharynx, leading towards the narrow tubular passage called oesophagus into a sac-like structure called crop which acts as a storage organ.

(iv) The crop is further followed by gizzard (proventriculus). Gizzard the structure composed of thick circular muscles and thick inner cuticle forming six highly chitinous plates called as teeth. It associated with the grinding and crushing of food particles. Entire forgut is lined by a thick cuticle.

(v) Midgut or mesentron is about one-third middle part of alimentry canal. The internal lining of midgut is an endodermal epithelium of columnal cells raised into several small villi like folds.

(vi) Anterior most part of midgut surrounding the stomadaeal valve is called cardia and finger like blind processess are called as enteric or hepatic caeca, present the junction of foregut and midgut.

(vii) A ring of yellow filamentous structures formed between the midgut and hindgut are called Malpighian tubules help in the removal of excretory products from haemolymph.

(viii) Hindgut is the remaining one-third posterior part of alimentary canal. It is relatively thicker than the midgut is lined by cuticle and ectodermal epithelium.

(ix) Hindgut is differentiated into three parts, i.e., anterior ileum, middle colon and posterior rectum. Ileum is short and relatively narrower and its cuticle bears minute spines. Colon is the longest, relatively thicker and a coiled part of hindgut. Rectum is a small and oval chamber that opens out through anus.

A well labelled diagram of male reproductive system is shown below