[Cellular encapsulation of Contortylenchus diplogaster v. Linser. (Nematoda: Allantonematidae) in the fat body of Ips sexdentatus Boern. (Coleoptera: Scolytidae) (author's transl)].

The parasitic females of C. diplogaster may induce the formation of cellular capsules in I. sexdentatus. This capsules may be free in the body cavity or attached to the fat body of the Insect. Each of them contains one parasitic female accompanied by its eggs and its larvae. They correspond to hypertrophied fat body cells, which become a syncytium. The larvae of Nematode which are inside the capsule, feed on this, and the older capsules are only bags filled with larvae, which will end by breaking themselves and by setting free their content in the body cavity of the host. The phenomenon, here observed in a Tylenchoïdea of which the Insect is the sole host, seems widely distributed in parasitic Nematodes of Insects, for it is already known in the Spiruroïdea and Filarioïdea. Otherwise, while the parasitic adults of all other species of Allantonematidae are considered to be free in the body cavity of their host, C. diplogaster may have a part of its life cycle inside the fat body of the host.