part_of adult ovary adult ovary stage I oocyte Fig. 16-8, in Biology of Ticks ISBN:0-19-505910-7. TADS:0000408 TADS:0000408 These are the earliest stage in the development of the oocytes that appears soon after attachment and the commencement offeeding in ixodid ticks or soon after the blood meal in the fast feeding argasid ticks. Stage I oocytes bulge externally on the outersurface of the ovary, appearing larger than the interstitial cells but with little additional cytoplasm. Stage I oocytes areprevitellogenic (i.e., lack yolk). default_namespace cell