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Summary is absent.

The parasite developmental period in the intermediate host, the mollusk Semisulcospira cancellata, is established. Some problems of the biology of larval stages of Metagonimus yokogawai are studied. On the basis of the analysis of temperature in rivers the possible emergence periods of cercariae from mollusks are established as well as the time of the highest extensity and intensity in the infestation of fishes with metacercariae of M. yokogawai.

Three new species of dicrocoeliids were found in birds of Central Tien-Shan: Platynosomum pyrrhocoraxi sp. n. from Pyrrhocorax pyrrhocorax, P. kirgisensis sp. n. from Anthus campestris and Brachylecithum tjanschanica sp. n. from P. pyrrhocorax.

Dactylogyrus nasalis Strelkov et Ha-Ky, 1964 is a stenothermic psychrophilous parasite occurring in autumn and winter at a temperature of 2 to 14°, in shallow waters 1.5 m in depth, on the young of carp fishes up to two years in age. On the larvae of fishes the parasite occurs at first on the surface of the body and fins and later on the gills and in nasal cavities as the larvae developed. The life span of the worm is 5 to 6 months.

A comparative study was conducted of the consumption of amino acids by Ascaris suum and Ascaridia galli, the nematodes being maintained at different amino acid media. A conclusion was made on the adaptation of the parasite's protein metabolism to the protein metabolism of the host. Experimental data suggest that the metabolic process in A. galli is more intensive than that in A. suum and the consumption of amino acids by ascarids proceeds by means of their active transport.

Four new species of mermitids from the larvae of midges are described. Agamomermis gluchovae sp. n. and Gastromermis beggii sp. n. were collected in the Pskov region, the two other species, Heleidomermis ovipara sp. n. and Spiculimermis mirzajevae sp. n. — in the Tunkin valley of the Burjat ASSR. H. ovipara in contrast to the typical viviparous species H. vivipara Rubz. is an oviparous one. The last moult proceeds in the host (in larvae of older instars). The host's infestation with this species exceeds 60 per cent in some populations.

A diagnosis and figure of a new nematode species of the genus Paratylenchus are given. The species was found in the root system of Abies nephrolepis Maxim. in the Dalnegorsk region of the Maritime Territory. P. abietis Eroshenko sp. n. is close to P. straeleni differing from the latter in the structure of the cephalic end, oesophageal corpus and the location of hemisonid in relation to the excretory pore.

Electrophysiological studies were conducted on the tick Hyalomma asiaticum P. Sch. et E. Schl. in regard to the Haller's organ responses to the odour of white mice, their blood, the valerian acid odour and to the respiration of man. Bioelectrical activity was registered by means of the wolfram microelectrode. At the registration of the background activity the number of amplitudes of impulses varied from three to ten in various ticks but was constant during an experiment for one specimen. The effect of any stimulus caused changes in the frequence of impulses in comparison to the background. The amplitude analysis of the Haller's organ responses has revealed the differences in them and suggests the presence of receptors or their groups in this organ responding selectively to qualitatively different stimuli.

Studies of the ecology of ixodid ticks, which were conducted in Turkmenia in 1964 to 1972, and avaiable literary data enabled the author to distinguish four types of parasitism as follows: nest-burrow, pasture-watching, pasture-burrow and indoor-pasture (synanthropic). The author suggests the following four types of the development: one-, two-, three-host and mixed types of the development. A table showing a relationship between these types is given.

The methods of rearing and cultivation of bloodsucking species о fthe genus Aedes were studied under the conditions of laboratory and laboratory-field experiments. Four mass species, Ae. communis, Ae. diantaeus, Ae. pionips and Ae. punctor, were used for investigation. The development rate of larvae and pupae, emergence, copulation and life span of adult mosquitoes were studied for the evaluation of the elaborated method.

The paper presents results of investigations on the biology of one of subdominating taiga-forest species under conditions prevailing in the Maritime Territory. The paper considers, in paricular, the quantity and periods of the flight in different regions of the Territory. The data are given on the duration of the gonotrophic cycle and emblryonal period, on the fecundity and life cycle.

The maintenance of pupae of 10 species of horse flies under constant and variable temperature conditions enabled the author to establish the duration of their development. Pupae of the genus Chrysops have the shortest and pupae of the genus Tabanus the longest developmental periods. Pupae of Hybomitra and Haematopota occupy an intermediate position. A temperature of 25 to 29° is optimal for the development of pupae. Depending on the species belonging the lower threshold of the development varies from 5.7 to 10.1° and a sum of effective temperatures from 93 to 192 degree-days.

It was established that in the steppe zone of eastern Georgia gad flies are active from 6.30 a. m. till 20 p. m., in the foothill zone — from 6 a. m. till 21 p. m. and in the subalpine forest of the Great Caucasus — from 8 a. m. till 19 p. m., excluding the crepuscular species Tabanus subparadoxus N. Ols. which is active till 21 p. m. The lower and optimal temperature limits of activity for different species are given. The effect of weather conditions on the activity of gad flies in the above landscapes was studied.

It was established that louse flies cause 100 per cent affection of elks and roes. They feed 15 to 20 times a day and suck during a feeding 0.0002 to 0.0003 g of blood. The bites of louse flies cause hyperemia, the formation of papules on the skin of dogs, rabbits, guinea pigs, white mice and pigeons.

A role of blood components (plasm, leycocytes, erythrocytes), defibrinated and haemolysed blood in the plague block formation in fleas was studied. The formation of blocks depends on native erythrocytes, their content in a unite of blood volume sucked out by a flea and on metabolites which are formed during their decay in the gastro-intestinal tract of the flea. The ability of the plague microbe to miltiply actively in the gastrointestinal tract seems to depend on its power to assimilate carbohydrates.

Studies were undertaken of the endogenic stages of Eimeria erythrourica, a parasite of Meriones erythrourus Gray. Localisation sites and periods of the appearance of all endogenic stages were determined. The successive stages of the growth and development of schizonts of different generations, macrogametes and microgametocytes were described.

A study was made of the fine structure of extra- and intracellular sporozoites and merozoites of Eimeria tenella. At these stages the pellicle consists of three unit membranes. The number of subpellicular microtubules in the merozoite was 22 and that in the sporozoite was 24; the typical conoid structure was observed. 2—3 paranuclear bodies were seen in the cytoplasm. The rhoptries — micronemes relationship is discussed.

Extremely small sizes and the complexity of the life cycles of microsporidians require individual methods of work with these Protozoa. The paper describes the main techniques used in the woork with microsporidians under field and laboratory conditions.

Mosquitoes Culex pipiens molestus quickly develop resistance to a preparation of pathogenic fungi, boverin. Heightened doses of this preparation (8 g/m 1.5 mid of concentration) caused the death of 94% of the first generation larvae and only of 48% of the 8-th generation larvae. An increase of the dose to 480 g/m 1.5 mid of boverin caused the death in 76—78% of water stages of 12-th to 14-th generations.

Summary is absent.

Summary is absent.