All the trypanosomes are very much alike.

They contain a nucleus represented by the dark area in the centre and a fur-like membrane terminating in a long whip-like flagellum.

They have the power of very active motion within the blood.] 2.

Diseases which are localized in the blood are transmitted by biting flies.

The biting apparatus becomes contaminated with the organisms contained in the blood, and these are directly inoculated into the blood of the next victim.