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Investigations undertaken in the USSR have revealed five autogenic of 21 species studied. Detailed studies of Culicoides riethi and C. puncticollis collected from the Issik-Kul and Donezk districts have established 100% autogenity in C. riethi and have shown that C. puncticollis is always a non-autogenic species. Maintainance of IVth stage larvae of C. riethi in pure water without food has shown that starvation of larvae does not affect the per cent of autogenity of hatched females (it remains 100) but reduces the fecundity of autogenic clutched of same females. Similar preliminary data were obtained for C. circumscriptus and C. salinairus. Analysis of autogenity of bloodsucking midges suggests that this is an additional advantageous for species adaptation to decrease mortality during Ist gonotrophic cycle and to maintain the quantity of the species in the absence of the host rather than a tendency to give up bloodsucking as such.

The structure of the head and its appendages was studied in females belonging to 75 species of mosquitoes (Culicidae) from the Soviet Union. Some characters were found to be of diagnostic importance. A brief description of taxonomic characters and characteristic of generic differences are given.

During parasitism in the host larvae of Oedemagena tarandi L. increase their weight over 20.000 fold. Absolute weight of larvae starts to rise after the formation of fistula but their growth rate slows down with age. The larval growth rate in different sex- and age groups of deer is different. Mass fall out of larvae occurs at the end of April or in May that depends on weather conditions prevailing in the spring period. Almost 2/3 of larvae fall out in daytime.The flight of warble flies begins in the middle of June and ends in the western part in the first half of July and in the eastern part in August. Attacking intensity of females is much higher in the east than that in the west. On cloudy days the flight activity falls down but probability of infection rises.

Ectoparasits exchange was found to exist between great gerbils and large-toothed sjusliks. Radioactive tracing of animals has shown that the intensity of parasitic epizootic contacts between them is relatively high. The number of fleas kept during 24 hours on one infected souslik and then passed to gerbils varied in the experiment from 0.66 to 2.0. The same index for fleas tagged on gerbils was 0.44.

By individual dose infection of fleas Xenopsylla gerbilli minax, with microbes of plague (alive or killed by heating) and subsequent studies of insects for the presence of viable agents or lysis zones it was established on the layer with Micrococcus lysodeikticus that the stomach of fleas contains lysozyme. However, the bactericid effect is associated not only with the presence of lysozyme but with other now unknown components which, apparently, are efficient in destroying P. pestis. The effect of bactericid factor is facilitated in hypotonic medium with lesser relative blood content. Specimens of P. pestis reared at 37° are more susceptible to bactericid factor that those cultivated at 28°.

New genera and species of trematodes are described from marine fishes of India as follows: Krusadaitrema chanosi gen. et sp. nov. from the intestine of Chanos chanos (Forsk.), Paradactylostomum indicum gen. et sp. nov. from the intestine of Engraulus telara (Ham.), Malabarotrema indica gen. et sp. nov. from the intestine of Entroplus suratensis (Bl.), Chauhanotrema indica gen. et sp. nov. from the intestine of Hemirhamphus far (Forsk.). A new subfamily Chauhanotrematinae subfam. nov., is erected.

572 specimens of mammals from Taimyr and Evenkia were examined: Lemmus sibiricus, Microtus middendorfi, M. oeconomus, Clethrionomys rutilus, Dicrostonyx torquatus, Ondatra zibethica, Ochotona alpina, Lepus timidus, Rangifer tarandus. Eight species of teniid larvae were recorded from these mammals. Of them, Taenia martis, T. mustelae, T. polyacantha, Alveococcus multilocularis occur in Muridae, and T. parenchymatosa, T. crabbei, T. hydatigena, Echinococcus granulosus in wild reindeer. The infection rate of wild deer is lower than that of a domestic one. In Muridae from Taimyr there were found larvae of helminths, the mature stages of which are normally parasitic in Carnivora and Mustelidae while in Evenkia occur only those species whose definitive hosts are Mustelidae.

Studies were carried out of the arginine and lysine consumption from casein hydrolysate by nematodes, Ascaris suum and Ascaridia galli. Parasites consume the above amino-acids completely and simultaneously in the medium rises the concentration of leucine with isoleucine and valine with methionine. Helminths kept in vitro and exposed to protein hydro lysate excreted primarily ammonia (70 to 80%) as comrared to urea. This suggests that the medium is favourable for maintenance of helminths as far as the latter were referred by most specialists to animals with ammonotelic type of metabolism. Despite the evident difference in hosts and systematic positon of parasites there was no disagreement in the consumption and excretion of amino-acids.

It was established experimentally that during its life cycle each Trichinella male is able to fertilize several females and the latter copulate several times in the host's intestine.

Parasite fauna of this year brood yearlings, two years brood and five years brood of the Ctenopharingodon idella from pond- and spawning-nursery fisheries was studied in connection with the acclimatization of phytophagous fishes of the Chinese complex in the delta of the Volga. 18 species of parasites were found in fishes of which 13 were obtained in the delta of the Volga. Four new species were brought into this region with the C. idella viz. Balantidium ctenopharyngodonis, Dactylogyrus lamellatus, Amurotrema dombrowskajae, Sineragasilus major.

Four freshwater and one anadromous forms of the Arctic char were recorded from Lake Azabachye (Kamchatka). The above forms inhabit different ecological niches and therefore differ in their parasite fauna. Certain parasites can be used as indicators of these forms. Further investigations in this field will provide an elaboration of a new method for differentiation of the Arctic shar forms by means of parasites — indicators.

Nematodes of the genus Neoaplectana are characterized by a symbiotic connection with bacteria, the presence of which determines the virulence of the nematode culture. By mass cultivation of Neoaplectana carpocapsae agriotos isolated from click beetles, using the wax moth as an object of infection, methods were improved for insect infection with nematodes, culture maintenance and medium productivity increase.

Studies of epizootia of microsporidiosis in populations of Aedes caspius caspius in the Kura-Araksinskaya lowland and foothills of Azerbaijan (1969—1970) have revealed a high level of infestation of mosquito larvae with microsporidians during the whole vegetation season. Variations in the infection of larvae in different water bodies were from 0 to 90% and in mean monthly infection from 30 to 60%. In the lowland there are two peaks of the infection curve, in spring and autumn with the fall in midsummer, while in foothills there are three peaks of the infection — in spring, midsummer and autumn.

Using methods of cytochemistry, the distribution of haemoglobin and total protein was investigated in the Armenian rock-lizard red blood cells, both intact and infected with haemogregarines. Haemoglobin was shown to disappear progressively from the infected cell, whereas the total protein amount remained almost unchanged. This evidence, along with a well-known fact that the host cells infected with some haemogregarine forms become hyperthrophied, may suggest some definite metabolic changes occurring in the infected erythrocyte. The latter seems to produce additional specific proteins whose production may be induced by the intracellular parasite.

A new subspecies of Allocreadium montanus Sidorov et Butenko, 1966 is described from Chizopygopsis stoliczkai, Szhizothorax infermedius and Nemachilus stoliczkai. Lenght of body 1.35—3.45 mm, maximum width 0.45—1.034 mm. Ratio between suckers is 1 : 1.4—1.9. The subspecies differs from A. montanus in the extention of yolk glands and position of ovary and genital bursa.

Ixodes lividus, a specific parasite of sand martins, was found to occur in nests of these birds in the south, west, centre and north-eastern part of the Leningrad district. Ticks were present in all active stages both in spring (49 nests) and autumn (78 nests). In both cases larvae were rarely dominant, nymphs occurred and adults were represented by males and females.

Summary is absent.

Summary is absent.

Summary is absent.

Summary is absent.