[Paraiotonchium osiris (Iontonchiinae : Tylenchida), a new species of nematode of the zoophilic fly, Musca osiris Wd].

The description and figures are given to the nematode Paraiotonchium osiris sp. n. parasitic in the body cavity of Musca osiris and in the genital organs of the host females from Turkmenia. Two morphologically different generations of nematodes, gamagenetic and parthenogenetic ones, develop in the body cavity of the insects. Juvenile females of the gamagenetic generation: n=11; L=474.6 to 587.6; a=15.02 to 22.1; c=5.23 to 6.97; V=(71.5 to 77.7); St=13.0 to 16.1. Mature parasitic females of the gamagenetic generation: n=14; L=1028.3 to 2695.1; a=8.79 to 18.04; c=8.51 to 15.9; V=(76.2 to 84.6); St=21.0 to 27.0. Parasitic females of the parthenogenetic generation: n=7; L=813.6 to 1412.5; a=8.24 to 13.15; c=9.94 to 17.92; V=(88.2 to 91.9); St=14.0 to 16.5. Males: n=30; L=469.2 to 803.8; a=17.0 to 29.12; c=4.5 to 6.99; St=7.5 to 14.0; Sp (d)=18.4 to 23.0; Sp (pr)=34.5 to 41.4; T=(62.41 to 83.57). The new species differs from two other members of the genus Paraiotonchium in the structure of the spicules (a longer distal portion) and a larger bursa in males. A key to the species of the genus Paraiotonchium is given.