Proc. Zool. Ins!. Kuss. Acad. ScL, 2S9. 2001: 67-74 Diversity and trends of the evolution of testes in Psocidea Alexander P. Emeljanov, Natalia V. Golub & Valentina G. Kuznetsova Zoological Institute, Russian Academy of Sciences. [Iniversitetskaya nab., I, St.Petersburg, 199034, Russia Variation of the number and mutual position of seminal follicles in males of Psocidea is considered. Literature data on all taxa involved (Nitzsch, 3882; Snodgrass, 1899; Pavlovsky, 1907, 1922, 1923; Badonnel, 1934; Jemsch, 1939; Finlayson, 1949; Ferris, 195];Klier, 1951; Mukerji & Sen-Sarma, 1955; Blagoveshchensky, 1956; Wong & Thorntom, 1968; Vishniakova, 1970; Saxena & Agarwal, 1981) and data on Psocoptera ob- tained by the second author (Golub, in press) have been used. Preparations of testes of Anoplura made by the late D.I. Blagoveshchensky and depos- ited at the Zoological Institute RAS in St.Petersburg have been also used. Reasoning on the pathways of morphological evolution of different taxa of Psocidea is based upon phylogenetic schemes of Smithers (1972), Vish- niakova (1964, 1987), and New (1987) regarding Psocoptera, and upon schemes of Konigsmann (1960), Clay (1970), Kim and Ludwig (1978), and Lyal (1985) regarding Phthiraptera. Female reproductive system of Psocidea was not considered specifi- cally. It should be noted, however that in Psocoptera variations in the number of ovarioles are insignificant and have the character of a simple oligomerization and/or polymerization. In all three suborders of Pso- coptera 5 ovarioles per female ovary occur. All studied species of the psocopteran suborders Trogiomorpha and Troctomorpha, as well as of Phthiraptera are characterized by five ovarioles per ovary. Only in the advanced psocopteran suborder Psocomorpha this number declines consecutively to 4 and 3. The evolutionary changes of testes are much more remarkable and com- plicated. In Psocoptera there are several essentially different types of testes: (I) unifollicular, (2) trifollicular with consecutive arrangement of follicles (comb-shaped lestes), and (3) trifollicular with fan-shaped arrangement of follicles (stems of all follicles converge at one point). Apart from these ma- jor types the only case of testes with 4 follicles is known in Caecilioides sp. (Caeciliidae, Psocomorpha), arrangement of follicles being consecutive as in variant 2 (Wong & Thornton, 1968). This is undoubtedly a secondary phenomenon.