- The stage of development of certain flagellate parasites of vertebrates in the insect host, such as the multiplying form of the agent of African sleeping sickness in the tsetse fly.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Examples from the Web for crithidia
The forms which pass into the intestine quickly assume the Crithidia form and continue to develop rapidly under this form.Handbook of Medical Entomology
William Albert Riley