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To establish the circulation of bovine sarcosporidia among wild animals of Uzbekistan foxes and young wolves were fed with bovine hearts and oesophaguses containing cysts of Sarkocystis bovicanis (=S. fusiformis). These animals were proved to be the final hosts of this species in nature. The prepatent period of S. bovicanis was found to be 7—8 and 7—9 days in foxes and young wolves, respectively and the patent one 33 and 28— 34 days, respectively.

Experiments conducted have shown that water temperature can affect dactylogyrids in two ways. From one hand, the direct influence stimulates the development and reproduction of the parasites that results in the increase of their abundance. From the other hand, the indirect effect can take place. The rise in the temperature increases the general resistence of the fish organism and favours the formation of immunological reaction to hyperinfection that causes the further fall in the parasite abundance. Thus, the seasonal dynamics of the abundance of dactylogyrids depends on the complex interaction of these two factors.

Studies of the development of Paricterotaenia porosa in its intermediate host Chironomus sp. were carried out. At 20° C the development of the larva is completed in 24 days. The primary cavity is formed in 9 days, the separation of the cercomere anlage — in 11 to 12 days and the invagination of the larva — in 19 days. The larval development of P. porosa is characterized by its passing in the cavity of the external cyst, by the complete separation of anlages of the body of the larva and cercomere at the metamere stage and by the intensive growth of the cercomere after the invagination of the larva. The analysis of the cercomere structure suggests its protective function.

Three new species of trematodes, Adinosoma gaevskaye sp. n., Tetrochetus mitenevi sp. n. and Antorchis spinosus sp. n., are described.

585 specimens of the mollusk Acroloxus lacustris were parasitologically investigated in the Divichin Bay of the Caspian Sea. 3 species of cercarians (Echinostoma sp., Echinoparyphium recurvation, Asymphylodora sp.), 2 species of parthenites (Echinostomatidae gen. sp. Redia I, Echinostomatidae gen. sp. Redia II) and 4 species of metacercarians (Metacercaria gen. sp. I, Metacercaria gen. sp. II, Metacercaria gen. sp. III, Tetracotyle sp.) were found in the specimens examined. A. lacustris is first reported as an intermediate host of trematodes.

Extracts from larvae of Trichinella spiralis, mature Ascaridia galli and Ascaris suum and blood sera of their possible hosts (rats, pigs, chicks, guinea pigs, mice and men) were investigated by the method of electrophoresis in polyacrylamid gel. The protein component was found to be most identical in helminth and its obligate host. The host specificity is supposed to depend on the community of the protein content of the parasite and its host. The data on the difference in protein spectra are given and the peculiarities of the evolution of mono- and polyhost helminths are discussed.

LDH isoenzymes of Trichinella larvae isolated from experimentally infected guinea pigs were investigated between days 30 and 400 inclusive after infection. It was found that on the 30 th day after infection the larvae have two isoenzymes while from the 40th to the 400 th day — three isoenzymes. The first of the latter is of fast responce and is located in the anod area near the indicator while the two others are of slow responce and are located between the isoenzymes LDH-3 and LDH-5 of the muscular tissue of guinea pigs. This indicates that energetic metabolism of Trichinella larvae proceeds in muscular tissues by aerobic and anaerobic way. Since electrophoretic specificity of LDH-isoenzymes of Trichinella larvae differ from that of LDH-isoenzymes of muscular tissue the former are apparently characteristic of Trichinella larvae.

Binema sp., Thelastoma skrjabini Sergiev, 1923, Psilocephala psilocephala Rao, 1958, Talpicola ornata (Travassos, 1925) Kloss, 1959, Talpicola sp. were found in Gryllotalpa gryllotalpa of Turkmenia.

The description and figures of two new species of nematodes of the genus Tylenchorhynchus Cobb, 1913 are given. T. variannus sp. n. is characterized by an asymmetrical position and variation of the width of cuticular rings in the trophic, genital and caudal parts of the body. It differs from T. irregularis Wu, 1969 in the shape of the stylet and tail and in the number and width of the tail rings. T. chirchikensis sp. n. differs from allied species by the protrusion of the cuticle into the body around the vulva, length of the ovary, structure of the head capsule, stylet and tail and b.y the ratio between the tail length and body width of the anus.

The parasite fauna of fishes of the Murgab river basin (the Bartang, Murgab, Oksu rivers and Lake Sarez) was first investigated. 44 species of helminths, protozoans and crustaceans were recorded from the above area. The ecological analysis of parasite fauna of Schizothorax intermedins, Schizopygopsis stoliczkai and Nemachilus stoliczkai was conducted and the factors affecting its distribution in different parts of the basin and in different species of hosts were established. The data were obtained on the peculiarities of parasitological processes in water bodies investigated.

The paper presents data on the population density of active ticks in different landscape zones of West Sykhote-Alyn as well as the material on the absolute abundance of ticks in four experimental 400 m² areas. The abundance of active Ixodes persulcatus and Haemaphysalis japonica on vegetation at the peak of their activity was found to amount to half of all hibernated adult ticks.

6 species of the genus Miyatrombicula are recorded from the fauna of the USSR: M. esoensis, M. reptilica, M. muris, M. balcanica, M. caucasica, M. ramitensis sp. n. Characteristisc of the genus, redescription of known and description of new species are given. Larvae of the mites parasitize in general small mammals. In addition, some of these species were found in West Europe, Japan and North America.

For cultivation of Aedes togoi the aquatic infusion of fallen leaves, peat and dry sphagnum (0.15°/0oS) was used and a larval diet (children's haematogen with an addition of polyvitamin "Undevit" and glutamic acid) was offered. Such cultural medium provides a rapid development of larvae and their survival, high stable weight of pupae, high fecundity and viability of imago. 7 generations were obtained without reducing the quality of culture.

The description of female, male and 4th stage larva of a new species of mosquito, Aedes (Stegomyia) sibiricus, from Siberia and Far East of the USSR is given. This species belonging to the albopictus subgroup of the scutellaris group of species was formerly confused with A. (S.) galloisi Yam. The geographical distribution of A. sibiricus is related to the south of the East taiga and Okhotsk districts of the Euro-Siberian province of the Circumboreal subregion of the Palearctic, while A. galloisi is spread in the Chinese—Himalayan subregion and has been recorded in the Soviet Union from the Sakhalin Island only (the geographical distribution of this species is shown on a map).

A new species of mosquitoes, A. gutzevichi, is described. According to its structural peculiarities the species belongs to A. caspius group. According to the taxonomic characters (Gutzevich, Monchadsky, Stakelberg, 1970) larvae and females of the mosquito are close to A. mariae but differ from the latter in many morphological and ecological features. By the structure of hypopigium males belong to the group of the species A. mariae and A. pulchritarsis but differ from the former in smaller basal warts and approximated lobes of IXth tergite and from the latter in the square shape of phallosome, approximated lobes and in the absence of the thorn on the basal wart. Larvae of A. gutzevichi differ from all palaearctic species of Aedes in the size of siphon, its pubescence and pigmentation of hind valve of the stigmal plate.

The study of the midgut of Hybomitra schineri by means of electron microscopy has shown that epithelial cells are of cylindrical shape. According to the electron density of cytoplasm the cells can be arranged into three subtypes. The apical surface of all the cells is covered by microvilli with filamentous glycocalyx. The peritrophic membrane of the 1st type is formed in females only during the blood digestion. Two types of secretion of digestive enzymes (merocrine and macroapocrine ones) were found, the latter being prevalent at the carbohydrate feeding.

The name of the previously described Lyperosomum soricis (Bychovskaja-Pavlovskaja, Vysotzkaja, Kulakova, 1970) proved to be preoccupied. A new name for the species is propozed: L. transcarpathicus.

Two types of fungus cells from various species of prey gamasid mites from West Siberia were found. By their form and structure the cells can be referred to the resting spores of entomophthoraceous fungi.