MORPHOLOGY OF THE FOVEAL GLANDS AND FOVEAE DORSALES IN MALE HYALOMMA-TRUNCATUM AND RHIPICEPHALUS-EVERTSI MIMETICUS TICKS (ACARI-IXODIDAE) BEFORE AND DURING FEEDING

The ultrastructure of the foveae dorsales and foveal glands in unfed a nd attached male Hyalomma truncatum and Rhipicephalus evertsi mimeticu s ticks was studied. Both species are provided with a paired foveal gl and system, which is similar in unfed as well as in attached ticks. Th is gland system consists of the fovea dorsalis with pores and pore tub es as the external part, the foveal neck zone as a link between the fo vea dorsalis and the lobes of the gland and the bulbous lobes as the i nnermost part. The fovea dorsalis is located on either side of the dor sal midline in the midsection of the body and appears as a roundish pl ate containing 15 +/- 6.5 and 21 +/- 7 slit-like pores in R. evertsi m imeticus (n = 210) and H. truncatum (n = 210), respectively. Each pore leads into st cuticular lined channel containing a pore tube. Below e ach fovea, the foveal neck zone is located within a groove of the cuti cle and consists of the termini of the pore tubes which enlarge basall y to form a cup-shaped ampulla each. Furthermore, secretory lobes are located below the foveal neck zone. Each lobe consists of secretory ce lls and a central excretory duct which leads into the ampulla. The duc ts are lined with microvilli. The secretory cells contain numerous ves icles of varying size with one or more granules. In male ticks of both species the secretory lobe cells remained unchanged in size, structur e and granule content irrespective of whether they were unfed or attac hed for up to 30 days. Axons occur in the fascicles between the secret ory lobe cells containing numerous neurosecretory vesicles. A possible role of the foveal glands in the production of pheromones is hypothes ized