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Analysis of the abundance of the tick O. papillipes in the Namangan and Andizhan districts was conducted on vast material. According to the tick abundance (from very high to very low) settlements were arranged into five groups, Most common are settlements with a high and average tick abundance. In most cases the agent of TRF was isolated from the ticks. Natural and anthropogenic factors determining the abundance rate of ticks in some settlements and possibilities of their practical use for the quick annihilation of TRF nidi are discussed.

357 specimens of the tick Ixodes pomerantzevi were collected during seven years in the south of Primorje Territory. The abundance of ticks is 0.96 per one animal and 8.5 females per 1 ha, on the average (all developmental phases) 0.231 per one animal in May—July. The abundance index of ticks increases in the years of depression and falls in the years of peaks of abundance of small mammals. The development of I. pomerantzevi 15 days, hatching of larvae takes place in 65 days after egg-laying, imagos moults for nymphs in 64 days after feeding.

Ixodes nipponensis is a common tick in the Khasan region southwards of the Sukhanov Ridge but it has not been recorded on the islands. I. pavlovskyi does not occur in southern and southwestern Primorje but is a common species on some islands. Haemaphysalis longicornis is reported only from the territory of reindeer farms. New data on I. crenulatus, H. flava and Dermacentor silvarum are given.

Pathology of gastrointestinal tract of Xenopsylla cheopis fleas infected with plague microbe was determined by means of electron microscopy. Ultrastructure of plague microbe during different periods of its stay in the vector was studied.

Larvae of Aedes dorsalis Mg. were maintained at the density of 0.05 and 0.5 spec./ml. It was noted that mosquitoes from overpopulated cultures grew smaller in size. The wings became shorter and more narrow by 4 to 6%. The wing reduction occurred on account of its distal elements (veins r3 and m2). Despite the decrease in the value of characters their variability decreased too, having increased only for wing width and vein mcu. In overpopulated cultures the wing length connection with veins r3 and m2 grew weaker in males while in females only such tendency was observed. Wing bilateral asymmetry was noted: left wing of females became wider and those of males wider and shorter. Analysis of variability of qualitative wing characters, which were singled out according to the venation pattern, has shown that of 9 studied characters only two depended on density (arrangement of corners of radial and medial vectors) and only in females. The role of such wing changes for swarming, active escaping from danger, direction and distance of flight of mosquitoes is discussed.

In 1981—1982 larvae of Ergasilus sieboldi occurred in the lake Arakul from the end of May to November. Two peaks of their abundance and biomass were recorded in August — September. Larvae were observed in great numbers at the depths of 1.3 and 7 m and in the surface layer of 1 m. During the developmental period over 98% of larvae do not survive.

A new species of cestodes parasitic in the intestine of Eumetopias jubatus from the Bering Sea is described. The species differs from other species of the genus in having larger scolex and eggs, different hosts and localisation site (large intestine).

Green light fluorescence characteristic of aminergetic neurons was revealed by means of hystochemical method with glyoxylic acid in the nervous system of redia, cercaria and marita of Echinostoma audyi, Philophthalmus gralli, Philophthalmus sp. The distribution of fluorescent elements is repeated in general at the above developmental stages iof trematodes and is associated with neuropiles and commissure of cephalic ganglia, with longitudinal nerve stems and transverse commissures. 2 and 3 pairs of relatively large aminergetic neurons have been found in redia, cercaria and marita, respectively. Fluorescent fibres innervate lateral processes of redia, tail of cercaria, mouth and abdominal suckers; they permeate somatic musculature.. This suggests the motor function of aminergetic elements. At the same time the endings of fibres at the body surface, especially in the anterior part, suggest their connection with receptors.

It was shown that pyruvate kinase (PK) in the supernatant fraction from Calicophoron ijijnai is able to regulate the direction of metabolic flow at glucose break down from phosphoenolpyruvate (PEP) level. The enzyme for activity required substrate, dinucleotides, cations K+ and Mn++. The activity with Mg++ as divalent cation is low. The addition of fructose — 1.6-diphosphate (FDP) did not affect the enzyme activity with Mn++, however, increased the affinity for PEP. The velocity of Mg++ activated reaction increased by 8.2 times in the presence of FDP. PK in C. ijimai is sensitive to ATP inhibition, being weakly inhibited by malate. L-alanine did not influence on the enzyme activity. The effect of some anthelmintic preparations on the PK activity was shown.

In the period of 1980—1981 the rate of infection of 6 populations of the littoral snail L. obtusata by trematode partenits was studied. The partenits of 10 species were found; the main part of the infection belonged to Microphallus piriformes and M. pygmaeus. Considerable differences in the rate of infection by partenits of different shell-colour phenotypes were discovered. The character of differences is similar in different populations and in the same population for different years. The influence of polymorphic system of shell's colour on the rate of infection in L. obtusata population is discussed.

10 species of arthropods are reported from scanty colonies of the northern pika Ochotona hyperborea Pall, from the Pripolar Ural. Only two species of ectoparasites are specific to members of the genus Ochotona, the sucking louse Hoplopleura ochotonae Ferr. and flea Amphalius runatus J. et R. Other species are characteristic of rodents inhabiting the same biotopes. The comparison of the material obtained with data on O. hyperborea from the principal part of its extensive distribution area indicates the impoverishment of the specific composition and decrease in the abundance of ectoparasities of this host in the isolated (due to Pleistocene glaciation) part of the distribution area which is remote from habitats of all members of the genus Ochotona.

Comparative study of diplogonadal diphillobothriids from different species of whalebone whales and from man (Japan) and analysis of literary data has made it possible to establish their identity. Only the species Diplogonoporus balaenopterae (Lönnberg, 1891) Lönnberg, 1892 capable of infecting whalebone whales, dogs and man can be regarded as really existing. The species D. grandis (Blanchard, 1894) Lühe, 1899 is its synonym.

A brief description of larvae of cestodes of A. arctica at their different developmental stages in experimentally infected collembola Onychiurus (Protaphorura) taimyrica and О. (P.) furcifer is given. Developed cysticercoids were observed 70 days after the infection. Collembola under natural conditions are supposed to be intermediate hosts of cestodes of A. arctica, parasites of reindeer.

The biological activity of a new organic compound β-diethylaminoisobuthironitrile was determined. A new phenomenon for nematodes of open-type larval development (Strongyloid) was found. Alive females of nematodes belonging to the genera Trichostrongylus, Ostertagia, Bunostomum and Haemonchus were treated with 5 volumes-% mixture of the compound with water. The development of eggs of these nematodes in the mother body and output of larvae in female were observed. The larvae lead an active mode of life, feed and are capable of developing. Optimal exposure of females in solution is 4 hours for Haemonchus and Trichostrongylus 2 hours for Bunostomum, and 3 hours for Ostertagia. Stimulation of egg development in nematodes of semidose and semi-open types was not observed.

A new species of parasitic copepods, Philoblenna littorina sp. n., is described. The parasite was found on gills of Littorina brevicula, L. mandschurica and L. squalida in the Gulf of Peter the Great.

Summary is absent.

Summary is absent.

Summary is absent.