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The midgut epithelium of H. asiaticum nymphs was studied by means of electron microscopy. It has been shown that during feeding the midgut epithelium of the above nymphs consists of three types of cells: reserve, secretory and digestive ones. There have been revealed two types of the digestive cells. The cells of the first type are capable for two forms of blood endocytosis: phagocytosis and pinocytosis. During feeding in these cells takes place fast intracellular digestion. This type of cells dominates at the beginning of feeding. The second type of digestive cells prevailing at the end of feeding is represented by specialized cells consuming only haemoglobin. A certain part of these cells preserves for a long time an intracellular reserve of haemoglobin.

Observations were conducted on the processes of feeding and oviposition in the females of Dermacentor silvarum poisoned with DDT, the ancestors of which had been subjected to this acaricide and had overcome the poisoning due to the feeding. The rise in the sensitivity to DDT in the females of the second generation and a number of pathological changes both in feeding females and in their progeny were noted.

504 nests of 11 species of birds were examined in the Volga-Kama state reserve. 57 430 specimens of Diptera belonging to 19 species and 13 families were collected from the nests. The schemes of the life cycles of Diptera, nest-burrow parasites of birds (Camus hemapterus Nitzsch, Stenepteryx hirundinis L., Protocalliphora azurea Fallen) are given and some moments of the ecology of nonparasitic species are illustrated.

Pathogenic effect of the crystalline exotoxine of Bacillus thuringiensis on the larvae of fleas was investigated. Deformities and changes in the functions of organs and tissues caused by the exotoxin in larvae and imago developed from the latter result in the premature death of the individuals (to 100%) or in the sterility of the remaining fleas.

The presence of phenothiazine in incubation medium of M. digitatus exerted the following effects: the increase of glycogene splitting and lactic acid excretion in aerobic conditions; the increase of acetic acid excretion and the decrease of α-methylbutyric acid excretion; glycolysis process inhibition in homogenates and supernatants during incubation with glucose. However, at phenothiazine incubation with FDF glycolysis intensity was unaffected.

The determination of the constant of the urea fission rate and study of the temperature dependence (activation energy) of the urease activity on warm- and cold-blooded animals in Ascaris suum and Contracaecum aduncum were undertaken. It has been shown that the constant of the urea fission rate in C. aduncum is more than an order of magnitude higher than that in A. suum. At a temperature of 17° the rate of this process in C. aduncum changes but little while in A. suum it practically ceases. On the contrary, at 47° the urease ferment activity in A. suum increases considerably while in C. aduncum the process rate does not rise as compared to that at 37°. The subsequent calculations of the energy activation have shown that a certain adaptation to definite conditions of ferments functioning can take place.

The distribution of residues of DDT and its metabolites (DDD and DDE) in tissues of Triaenophorus nodulosus and its host was studied. It has been noted that cestodes can accumulate chlororganic substances in great quantity. The ability of Bothriocephalus gowkongensis has been established to dechlorate pp-DDT and to excrete pp-, op- and mp-DDD from the organism. Pp-DDT decreases the glycogene content and causes the rise of amylolytic activity in the above cestodes in acute tests. The effect of pp-DDT on the locomotor activity of cestodes is of two-phase character. The first one is associated with the muscular influence, the second one — with neurotrophic effect. A high toxicity of mp-DDD (0.1 mg/l) for the locomotor activity of cestodes as compared with the effect of pp- and op-DDD was revealed.

The species P. diplodi Euzet et Cauwet, 1967, P. kuhliae (Yamaguti, 1968), P. mao-mao (Yamaguti, 1968), P. acanthogobii (Yamaguti, 1940), P. gerres (Sandars, 1944), P. tubicirrus (Paperna et Kohn, 1964) should be assigned to the genus Polylabris Euzet et Cauwet, 1967 (=Prostatomicrocotyla Yamaguti, 1968). Undoubtedly, "Microcotyle sillaginae Woolcock, 1936" in sensu Gupta and Khullar, 1968, and very likely the true Microcotyle sillaginae Woolcock, 1936 belong to the same genus. P. gerres (Machida, 1973) is a synonym and at the same time a homonym of P. gerres (Sandars, 1944). A new species, Polylabris acanthopagri sp. n., is described and a new genus, Polylabroides, with a single species, P. biungulatus gen. et sp. n., is proposed.

A topography of the genital system of Metastrongylus elongatus is described in comparison with the genital system of Dictyocaulus viviparus. It is established that in these species of helminths the genital tubes have a similar location but in Metastrongylus elongatus takes place an uterus lenthening caused by the transference of the genital orifice to the hind end of the body. Its total length is 2.5 as long as the body length of the worm. This phenomenon is regarded as an adaptation providing this species a possibility to produce eggs which can for a long time exist in the environment.

A study of the life cycles of some varieties of Glugea anomala has shown that the genus Glugea is a distinct genus having the following diagnosis. Sporoblasts and spores are formed as a result of step by step decay of the multinuclear Plasmodium situated inside the sporogonal vacuole (sporont). Ripe spores either remain connected together in groups with irregular (6 to 32) often uneven number of spores or lie singly, seldom in pairs. Microsporidia are able to cause extremely strong hypertrophy of the host's infected cell which is transformed into a round white cyst filled with the parasite's spores.

Tribolium destructor and T. confusum diseases caused by the fat body of the parasites Nosema whitei and Adelina tribolii were investigated. Life span and weight dynamics were examined at different temperatures and infection conditions. Infected females of T. confusum lay a less number of eggs. The gas produced by stink glands of T. destructor may inactivate the spores of N. whitei but does not affect those of A. tribolii.

4 new species of the genus Schoutedenichia are described and illustrated: Sch. zarudnyi sp. n., Sch. originale sp. n., Sch. abharica sp. n., Sch. shirazica sp. n. They have been found on small mammals in Iran.

Gamasid mites from voles and their nests were studied in the Volga-Kama state reserve. 28 species of gamasid mites are reported. The parasitic species Hypoaspis heselhausi Oudms., Haemolaelaps glasgowi (Ewing) and Laelaps hilaris Koch are most abundant. Data are given on the seasonal variations in the number of parasitic and free-living species.

Three species of the genus Culicoides new for science are described: C. oxianus Smatov, sp. n., С. pentamaculatus Smatov, sp. n., С. aquilinus Smatov et Kravets, sp. n. The specimens were collected in the Chimkent, Kzyl-Orda, Aktjubinsk, Turgai and Tselinogradsk districts.

In 1951 to 1973 there were recorded cases of myiasis in four species of Amphibia (Pelobates fuscus, Bufo bufo, В. viridis, Rana arvalis) from the Volga-Kama state reserve (the Tatar ASSR). In arid 1972 the number of Rana arvalis with myiasis reached ta 20—25%. Observations were conducted on the development of Lucilia bufonivora from the egg laying to the host death and hatching of imago.

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Summary is absent.

Summary is absent.