The testis and sperm of Mylabris indica (Thunberg) were studied histomorphologically using Transmission Electron Microscopy (TEM). On the basis of morphological observations of the testes of M.indica, the following structural organizations have been examined: the structure of a pair of testis contained a number of yellowish testicular follicles which are arranged in radials like that of clustered apple. Each testicular follicle is separated into connective tissue similar to that of higher vertebrate animals. Testicular follicles contained a number of small and large size cysts and different stage of germ cells. The spermatozoa develop and mature within the small cyst (each small cyst contain odd number (3 to 9 germ cells)), after maturation, the spermatozoa move to organized to large cyst and each large cyst contained 250 and more number of 7-13 sperm nest. The sperm consisted of a head (nucleus and acrosome) and flagellum (it consist two mitochondrial complex, axoneme 9+9+2 pattern, a pair of accessory bodies and centriolar adjunct was observed near axoneme). The more developmental characters such as structural organizations of testis and spermatozoa of M. indica are helpful to trace the phylogenetic evolution of insect species.
