Studies on three species of the genus Cystocephalus Schneider, 1886 (Apicomplexa: Eugregarinida: Stylocephalidae) with special reference to host specificity and distribution of members of family Stylocephalidae in Egypt.

Three species belonging to genus Cystocephalus, Schneider 1886 were found parasitizing three coleoptra hosts. Out of 105 Blaps polychresta, only one male was infected with C. algerianus and females were parasites free. Ten percent of examined Pimelia angulata Ten percent of examined Pimelia angulata (n = 30) were infected with the same parasite. Among are one male (5.56%) and 2 females (16.67%). Out of 126 of Trachyderma hispida 6 (4.76%) were parasitized by C. gabei. Only 3 males (5.1%) and 3 females (4.48%) were harbouring this parasite. Cystocephalus albrechti were found infecting 78 (61.9%) out of 126 of T. hispida. Forty six males (77.93%) and 32 females (47.76%) were infected. Males of the three tenebrionid hosts were more susceptible to infection rather than females. B. polychresta was considered a new host for C. algerianus in Egypt. Also, C. albrechti might be considered as specific host for T. hispida. Mid and hind gut appeared blackened in case of massive infection (> 240 parasites per host) of parasitized males of C. albrechti. The host specificity and the first biogeographical map fort distribution of stylocephalids and cystocephalids are provided here.