Studies on the genus Stylocephalus ellis, 1912 (Apicomplexa: Eugregarinida: Stylocephalidae) in beetles (Coleoptera: Tenebrionidae) from El Fayoum Governorate, Egypt.

Four species of the genus Stylocephalus Ellis, 1912 were recorded and described from beetles in El Fayoum Governorate; S. longicollis, S. phalloides, S. variabilis and S. eastoni. Both S. phalloides and S. variabilis were recorded in Zophosis sp. and Pimelia angulata, respectively for the first time in Egypt. Out of 105 Blaps polychresta, 18 (17.14%) were infected with S. longicollis and 57 (54.29%) with S. eastoni. Out of 30 Pimelia angulata, 17 (56.76%) were infected with S. variabilis and all examined Zophosis sp. (n = 67) were infected with S. phalloides. Scanning electron microscopy on S. longicollis revealed morphological features not reported before; three pairs of longitudinal ribs extending from the second fifth till the posterior extremity of old sporont and a minute pore on the anterior tip of epimerite. In S. eastoni, the epimerite-host epithelium relationship revealed that the parasite invades host's gut with the distal part of epimerite. Regarding the gross pathological symptoms, heavily infected hosts showed a sluggish motility, short antennae, swollen abdomen, lack of fat accumulation, and putrid smell in dead beetles.