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As hystological studies of hungry imago of Dermacentor pictus Herm. have shown changes in the cellular structure of the midgut epithelium and the decrease in its height (about 3 times) can serve as indicators of physiological age of the ticks. The structure transformation manifests itself in regular changes of the cells content of the midgut epithelium and numerical ratio between midgut cells of various types in ticks of different age. In new-born and young individuals digestive cells with haemoglobin dominate, new-born ticks are characterized as well by brown digestive cells. Epithelium of adult ticks consists of secretory and reserve cells, that of old individuals-mainly of reserve cells, specialized in accumulation of hematin, and rare secretory ones. Digestive and secretory cells are regarded as morphologically differing consequitive stages of the development of one kind of cells while secretory cells are considered to be their mature stage ready for feeding of an individual. It is assumed that in hungry ticks there are periods of more and less rediness for feeding while in adult ticks the best rediness for feeding is observed. Maximum development of secretory cells in midgut epithelium is the main indicator of mature age (Illrd physiological) of hungry ticks.

The paper completes the series of morphological investigations of the main distant receptor organ in the ticks of the family Argasidae by scanning and transmitting electron microscopy (Balashov a. Leonovich, 1977; Leonovich, 1979) and considers descriptions of the fine structure of Haller's organs of ornithodoid (O. moubata) and otobiinoid (Al. lahorensis) types. The summarising of the data on Haller's organ in argasids has enabled the author to suggest possible ways of evolution of this organ. An important role of transformations of different non-sensory structures in the evolution was shown. Characteristic features of the evolution of the organ in argasids are: morphologically progressive differentiation of a capsule (olfactory part of the organ) and reduction of an anterior group of sensilla.

912 hungry females of Ixodes persulcatus from 19 sites of their distribution area (from Estonia to the Kuril Islands) were measured. The length of the body and that of the dorsal shield reach their maximum in the Primorje and in the south of Khabarovsk territories. Northwards and westwards and on the islands of the Pacific ticks are smaller.

It has been established under laboratory conditions that in ticks O. papillipes there exists an intrapopulation regulation of their number depending on the population density. The course of the regulation is as follows: with increasing density decreases the fecundity of females, increases the mortality of eggs and imago, increases the duration of oviposition and development of eggs.

Investigation of sounds arising during the flight of four sympatric species of mosquitoes of the genus Aedes has shown that at 24C the main frequences of females are in the ranges of 308 to 404 Hz and those of males from 503 to 566 Hz (Fig. 1, Tab.). In the first instance interspecies differences vary from 20 to 96 Hz, in the second — from 11 to 63 Hz. It has been established by means of electrophysiological methods that Johnston's organs of males of A. diantaeus and A. communis at 24C respond to sounds of 80 to 500 Hz (minimum thresholds of reaction are from 27 to 30 dB) (Fig. 3.). Small differences between main frequences of sounds of females and optimal frequences of auditory organs of males depend on the temperature (Fig. 2) and can be accounted for by the body temperature of flying females increasing that of males. Johnston's organs of males respond to sounds of females of all four species.

Analysis of the parasite fauna of Salmonoidea from Eurasia confirms the hypothesis of the mountain origin of this group. The formation of the parasite fauna proceeded in three stages: mountain and foothills (mainly specific) parasite fauna; the formation of the main part of the parasite fauna in the plain districts of the rivers; the appearance of parasites marine in their origin but adapted to the life in fresh waters. The scale of differences between families and genera is estimated. The genus Salmo is most close to the ancestral forms. Brachymystax and Hucho are the most ancient genera in the family Salmonidae. The family Thymallidae was the first to separate itself from the ancestral forms; Coregonidae is the most young family. The genus Prosopium was the first to separate itself in the family Coregonidae.

Laterocotyle synaphobranchi gen. et sp. n. (the family Mazoplectidae Mamaev et Sliptschenko, 1975) from the abyssal eel-like fish Synaphobranchus kaupii John. from the northwestern Pacific is described. The types of formation of the unilateral haptor in higher monogeneans in the evolutionary history are discussed.

The development of the cercocyst of the cestode Paranoplocephala omphalodes (Hermann, 1783) in experimentally infected Onychiurus octopunctatus (Tullberg, 1876) and O. flavorufulus, Martynova, 1976 is described. At 25° and an average intensity of infection the morphogenesis is completed for 10 days. Mature cysticercoid of P. omphalodes, unlike larvae of other species of anoplocephalids, has a reduced neck. A technique of laboratory maintenance of springtails is described.

The influence of host species and its biomorphology on some features of a wide spread parasite of Coregonus sp. sp. was established. The formation of morphological features of cestodes is connected with a definite species or ecoform of host fishes. The differences in ecology and size of the host within a certain species are reflected in the anatomy of the parasite. It is suggested that only one species P. exiguus including morphologically different populations, depending on biology of the host, infects the coregonids of Karelia.

Seven species of cestodes are reported for Dendrocopos major and Junx torquilla. The species Passerilepis parina is redescribed and morphological description of other species is refined. The formation of embryonal hooks of Passerilepis passeris is described.

The paper describes glandular formations found in marites of four species of trematodes: Macrodera longicollis, Pneumonoeces asper, P. variegatus and Skrjabinoeces similis. Differences in morphology and localisation of these formations in species belonging to different systematic groups and their similarity in closely related species are noted.

The antigen activity of bile of rabbits, sheep and cattle infected with F. hepatica was investigated by the immunodiffusion method. The sera obtained from animals with experimental fasciolosis and other infections were used. At the experimental fasciolosis and intensive natural infection antigens were found in bile, one of which was present in all the animals and turned to be identical immunologically to the specific protein antigene (molecular weight is 27 500) isolated from the extract of F. hepatica. Titres of this antigene in bile depended usually on the infection intensity and were, as a rule, higher than titres of corresponding antibodies in the blood serum. The presence of this antigen in bile can serve as a diagnostic indication of fasciolosis especially when ovoscope or immunological methods based on the finding of antibodies are inefficient.

20-day old chicks were infected with Eimeria tenella, treated with coccidin (250 mg/kg) and free amino acids of the femoral muscle tissues were studied. The infection of chicks was accompanied with metabolism disorders of all amino acids of the muscle tissue excluding leucine, methionine, tyrosine and phenylalanine. During the treatment of infected chicks with coccidin the level of free amino acids re-established within 10 days. This preparation affected most of all metabolism of alanine, isoleucine, aspartic acid and glycine and was less efficient in the re-establishment of the level of araginine, lysine and threonine. It is suggested during the tests of coccidiostatics to take into consideration free amino acids of muscle tissues for the estimation of the efficiency of medical substances.

A new species of sandfly, Phlebotomus (Euphlebotomus) autumnalis sp. n., is described using two males and two females captured at three points in rocky mountains of the south-eastern part of Afghanistan, in October 1977 and 1978. The new species is close to P. mesghalii Seyedi Rasliti Nadim, 1970 but lias distinct differences in the shape of aedeagus and paramere (males), length of A3, pattern of the pharyngeal armature and number of segments in spermatheca (females).

Summary is absent.

Summary is absent.