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Some aspects of the ontogenesis of trombidiform mites belonging to the subcohort Parasitengonae are considered from the point of view of terminology, phylogeny, metamorphosis, life cycle, parasitism, etc. On the basis of morphological analysis of the development of trombiculid mites (Trombiculidae) the original scheme of sequential stages of their ontogenesis is suggested. It is shown that progressive process of the ontogenetic development is uninterrupted throughout the whole life cycle of these mites. The quiescent stages of the life cycle of Parasitengonae are not analogous to those of insect's pupa. The beginning and end of these stages are accompanied by two common molting cycles. However, the whole period of existence of quiescent stages should be named proto- and tritonymph. As transphasic morphogenesis does not occur in the development of Parasitengonae, morphological organization of developmental phases and their environment are not radically transformed, and quiescent stages exist as individual ones, metamorphosis in their ontogenesis does not take place. The pharate phase in the development of Parasitengonae corresponds to the already formed but not yet hatched larva, deutonymph and imago rather than to quiescent stages. The universal terms "stage" and "phase" are recommended for characterization of the development of trombidiform mites while the other terms should be rejected. Thesis that parasitism of larvae within Parasitengonae is evolutionally a younger phenomenon than the formation of initial organization of Actinedida and differentiation of their ontogenesis is also discussed. At the same time it is necessary to note that morphological organization of Actinedida in different branches shows a low level of system integration of their tissues.

Correlation analysis of 10 characters was run in three species of Dermacentor, D. nuttalli, D. ushakovae, D. niveus, and in Ixodes persulcatus, separately for each phase and sex. Correlation coefficients are very low in larvae of all species. In male nymphs correlation coefficients are on the same level in all species while the correlation coefficient level in female nymphs reflects the degree of independence of the development of characters. This defines the degree of manifestation of sexual dimorphism at the nymphal phase: the more rigid the connections between the characters, the less number of characters shows sexual differences. At the phase of imago the lowest correlation coefficients are in I. persulcatus. This species displays most distinct differences in the morphology of females and males. On the basis of comparison of correlation and variability coefficients the functional role of the characters is discussed.

A possibility of rearing Aedes togoi larvae in fresh water on simple diet and at the density of 50 larvae/dm² is shown. The mosquitoes were held in small cages up to 1 dm³. The larvae developed successfully at a concentration of NaCl from 0 to 4%, mosquitoes prefer to lay eggs in fresh water. It was concluded that the investigated strain is not salt-loving but salt-tolerant.

Observations on the body mass changes and behaviour of chaffinch (Fringilla coelebs) nestlings infected and noninfected with Haemoproteus fringillae as well as comparison of parasitemia level in raised by hand experimental nestlings and young (juveniles) birds, which were caught and shot in the field, testify to the pathogenicity of hemoproteids for their vertebrate hosts. The signs of illness were not observed on infected birds. At the peak of parasitemia the lowering of the locomotion activity of birds takes place. At the top of parasitemia for a three-day period the young chaffinches are weakly mobile. They demonstrate the secret reaction after frightening and prefer begging behaviour to independent feeding. As a result the heavily infected chaffinches are not taken into consideration by the methods of catching but may be obtained by shooting. The chaffinches mobility limitation during the peak of parasitemia not only assists the going through a heavy phase of infection but makes the birds more vulnerable to preys, unfavourable climatic, feeding and other factors as well. It means a reduction in the ability for competition of infected birds and leads to the increasing probability for the elimination of infected specimens in the field conditions. The notion on harmlessness of hemoproteids for the birds, and probably of other parasites too, obtained under experimental conditions (in a cage) cannot be applied to wild animals in the field without ecological tests. Ecological investigations may reveal the pathogenic effect of parasites which are known to be undangerous for the hosts in the cage.

The morphology of cestodes-dilepidids, corresponding to the first description of Taenia parvirostris Krabbe, 1869, was studied in detail on large material from swallows of the Ukraine. It has been established that the mature cestodes of this species can reach 27 mm in length and 1.35 mm in width. The scolex diameter is 0.127 to 0.139 mm; the proboscis armament consists, as a rule, of 28 to 32 hooks 0.011 to 0.013 mm long, arranged in one row, forming up to 10 festoons; testes are usually 20 to 24 in number; bursa of the cirrus 0.12 to 0.19 mm long lies in the lateral field; completely evaginated cirrus 0.05 mm long, with diameter of the basis 0.017 to 0.019 mm, is armed with spines; ovary alar up to 0.97 mm wide, uterus deeply-lobed. The described species is placed into the genus Hirundinicola Birova-Volosinovicova, 1969. The synonymy is given. It is shown that the specific name Vitta parvirostris (Krabbe, 1869) has been erroneously used until recently (Baer, 1959 and others) for a designation of the other species of the group, Hirundinicola chelidonariae (Spasskaja, 1957).

Hysterothylacium petteri sp. n. was recovered from the stomach of Xiphias gladius occurring in the Kuro-Shio. The morphological difference of H. petteri from all other species of this genus is the extremely long ventricular caecum (two times more than pharynx). The species is very similar to H. corrugatum Deardorff et Overstreet, 1980 from swordfish off the American shores and corresponds to the description of Hysterothylacium sp. by Petter, Maillard, 1987. The third stage larvae of H. petteri sp. n. are probably those larval forms which were described as Contracaecum sp. 1. Type IIA in Brunsdon in Boyle, 1966; Contracaecum sp. Otsuru et al-type-B (Kikuchi et al-type-A) in Kagei et al., 1970; Thynnascaris from Todarodes pacificus in Oshima, 1972; Contracaecum — type larva (B) in Shiraki, 1974; Hysterothylacium L3 in Weerasooriya et al., 1986; Porrocaecum sp. 1. in Gaevskaya, Nigmatullin, Schuchhalter. New morphometric data on these larvae are given.

Data are given on the specific structure of the parthenitae community of trematodes in 11 populations of the mollusk Pisidium amnicum. The mollusc is parasitized by 4 species of Trematodes. The dominant species in all the populations in B. luciopercae. The community structure of trematodes in molluscs from the middle and lower parts of the rivers in different. Changes in the structure of the community of trematodes depending on the host's age and the pollution of the water body are shown. Double invasions of molluscs are analyzed and interspecific relationships between trematodes are discussed.

Comparative studies were carried out of the isoenzyme profile of 10 isolates of Leishmania (members of the subgenus Sauroleishmania) recovered from different species of lizards of Turkmenia and some regions of Africa. Isoenzyme analysis was run with the use of electrophoresis on acetate-cellulose plates. For each isolate there was defined and electrophoretic mobility of 11 enzymes: G-6PDH, ALD, 6 PGDH, LDH, FK, GOT, HK, ME, PGI, PGM, ACP, 4 independent zymodems are recognized among studied isolates, which correspond to 4 species of Sauroleishmania: L. (S.) gulikae, L. (S.) gymnodactyli, L. (S.) adleri, L. (S.) tarentolae. It is shown that in the above species the greatest variability is characteristic of zymograms G-6PDH, LDH, FK, GOT, ACP. In contrast, zymograms HK and ME are practically identical in all studied isolates. The data obtained by isoenzyme analysis correlate well with the results of serological studies of the above parasites and with the results of restrictions analysis of their kinetoplast DNA.

Changes in the morphometric indices of fishes infected with Bothriocephalus acheilognathi, the activity level of digestive enzymes (amylase, protease, lipase, alkaline and acidic phosphatase) in fishes and in the body of Bothriocephalus as well as the dynamics of the desorption of enzymes from the digestive — transport surface of carp and cestodes were studied on the current year young reared in ponds of the fish farm "Nivka" of the Kiev region. The correlation between the activity of enzymes and morphometric characteristics of fishes and parasites was analyzed. It has been established that carp young with low size — weight indices is infected with a greater number of cestodes (3 to 34 spec.) than larger fishes (1 to 11 spec.). In fishes infected with Bothriocephalus a disturbance of the extracellular and parietal digestive processes is observed. The activity of amylase and protease functioning in the intestine cavity of infected fishes changes to a greater extent than the activity of enzymes of the mucosa. In Bothriocephalus the activity of amylase, protease and lipase is stipulated by the enzymes adsorbed from the content of the intestine while the phosphatase activity in cestodes depends, apparently, on the enzymes synthesized by helminths themselves.

The composition of fatty acids of lipids in the muscles of rats and larvae of Trichinella spiralis and T. nativa developing in them were studied. Both species are characterized by practically the same composition of fatty acids, only in the frost-resistant species T. nativa there was a sufficient amount (up to 3.5%) of docosapenta- and docosahexaenic acids (22 :5 and 22:6). The comparison of the content of individual fatty acids in larvae and in muscles of the host by means of statistical correlation analysis suggests that larvae obtain a considerable portion of palmitic acid from the host and transform in into necessary long-chain saturated and unsaturated fatty acids by means of elongating and desaturating enzymes. Changes in the contents of fatty acids in larvae extracted from dead rats, which during some days were undergone freezing at negative temperatures ( — 8 —10°), are the same in quality for both species. These changes can be explained if we assume that the activity of elongases and desaturases of Trichinella decreases with cooling to a greater extent than the supply of palmitic acid from the host's tissues. A higher frost-resistance of T. nativa may be associated as with a greater protection of enzymes in the membranes by long-chain polyene acyls so with a higher thermal stability of proteins themselves.

Infected mollusks Melanopsis praemorsa are able to endure not only long starvation but provide also special environment for the maternal redia development up to the emergence of daughter redia. At the beginning the mollusk-host affects chiefly the speed of the maternal redia development. Thus, the process of reproduction in starving mollusks was observed a week later than in control ones, which were regularly fed during the experiment. But the development of microgemipopulation under the conditions of host starvation does not go on. No cercariae were recorded in starving mollusks and soon after the emergence of daughter rediae snails die. It was found out that under the conditions of starvation the mollusk's life span is determined first of all by the temperature of the environment, irrespective of the infection rate. The maximum value of life duration is recorded at a room temperature, and life duration is reduced with a significant increase or decrease in temperature. A long starvation of mollusks, having at the beginning of the experiment a mature microgemipopulation of rediae, leads to a noticeable reducing in the number and sizes of cercariae produced by them. At the same time the daily rhythm of emission and behaviour of larvae are broken.

In horn snails infected with parthenitae of trematodes and in those free of infection, exposed for 48 hours to hydroquinone solutions (0.1—200 mg/l-1), the symptom-complex of intoxication and the pattern of pathological process are analogous. However, protective and adaptive properties of infected individuals, due to an additional functional load (invasion with parthenitae of trematodes), are rather weakened. In this connection, if concentrations of toxicant are the same, the corresponding symptoms of intoxication are displayed in these individuals earlier and stronger and protective-adaptive reactions begin "to act" considerably later and to a lesser extent than in animals free of infection. In horn snails infected with parthenitae of trematodes the sensibility to hydroquinone is considerably higher and stability is much lower than in noninfected individuals. The speed and degree of reversibility of different intoxication symptoms are much lower and the after-effect of the toxicant lasts much longer. Absolute values of the main toxicological indices, the range of LC0—LC100 and gradation of the pathological process in infected individuals are determined by the intensity of their infection.

101 species of oribatid mites and 12 species of helminths — anoplocephalats, transmitted by these mites, were found out by Soviet-Vietnam studies in agroecosystems and tropical forests of northern and southern Vietnam. Helminths were recorded from graminivorous mammals as follows: horses, zebu, sheep, goats, buffaloes, deer, hares, elephant, 2 species of rates, 5 species of monkeys and 11 species of birds.

Summary is absent.