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Data are given herein concerning the species structure and trophic links in nest-burrow coenoses of sand and house martins. The population of burrows and nests of martins has not been found to form an individual consortium as in them is accumulated only some part of consortive links of biocoenosis.

The digestion of blood by L. segnis was investigated by hystological and hystochemical methods. The protease activity in the stomachs of these flease was found to be very high. After the feeding erythrocytes do not stick together and fibrin precipitates only in a shape of filaments. As a result a dense clot of formed elements and plasma-proteins does not appear. Hemolysis of erythrocytes in adult fleas (maintained 7 to 10 days in the nest with the host prior to the test) ceases within 15—20 minutes while in young ones (up to 24 hours old) — within 1—1.5 hour.

In connection with building of hydrotechnical constructions and creation of water bodies the abundance of anopheles as in urban so in rural conditions was high that amounted to 120 to 690 females per a site of day's rest. By means of precipitation reaction in the capillaries with an extraction of stomachs' contents it has been established that in rural conditions hosts of anopheles are horned cattle while in urban ones — man and poultry.

Anomalohimalaya lotozkyi sp. n., the second species of this genus, was found in Tadzhikistan, Peter I ridge, at the height of 2700 m above the sea level in rocky locality with xerophilous vegetation on Alticola argentatus. In June, 1977 there were found larvae and nymphs of the species. After feeding larvae and then nymphs females and males were obtained. All phases of the life cycle differ distinctly from those of the type species An. lama Hoog., Kais. et Mitch., 1970, from Himalayas. The diagnosis of the genus Anomalohimalaya is specified. This genus combines the characters of Haemaphysalis Koch and Rhipicephalus Koch and is of great significance for more precise definition of phylogeny of the subfamily Amblyomminae Banks.

Experiments in vivo have shown that the ticks of Ornithodoros papillipes inhibit both Gram-positive and Gram-negative bacteria. Of Gram-positive microorganisms most sensitive to bactericidal effect of ticks have turned to be micrococci, staphylococci, streptococci and bacteria of diphtheria, of Gram-negative ones — Bacillus coli. Of Gram-positive microorganisms less sensitive were Listeria, of Gram-negative ones — salmonellae, agents of tularemia and pseudotuberculosis. At the infection with bacteria the organism of the tick produces a bactericidal substance which causes the dying off of the microbal population. The ability of the bactericidal substance to lyse the inhibited cells of Micrococcus lysodeiktickus as well as the coincidence of data on sensibility to the tick bactericidal substance obtained experimentally in vitro and in vivo have shown that lysozyme is an active antibacterial substance in the tick's organism.

Data are given on morphology of cercariae of the species Paralepoderma brumpti (Buttner, 1950), found in Planorbis planorbis from waters of the Crimea (Uk. SSR), and on morphology of progenetic metacercariae reared experimantally in tadpoles of Rana ridibunda.

Morphology, ecology and chromosomes of P. asperum and P. saginatum were investigated. The both species have a diploid set consisting of 20 chromosomes with similar morphology and size of bivalents. Their karyotypes are supposed to be identical. According to their morphology and ecology the both species are clearly differentiated. A conclusion is drawn on the distinct status of these trematodes having originated as a result of simpatric speciation.

Experimental studies have shown that when feeding beetles of S. sacer swallow eggs of Th. giardi together with faeces of horned and small cattle. After getting into the insect's intestine the eggs of Thysaniezia are eliminated in most beetles (from 91.1 to 100%) within one hour. Only in some individuals a very insignificant portion of the parasite's eggs remains viable within two hours. In beetles' faeces excreted by them in two hours and in subsequent periods after the feeding eggs of Thysaniezia were not found. The greatest eliminational ability was displayed by the beetles maintained without feeding for 1—2 days. The eliminational ability of beetles kept over 3 days (4 to 5) without food noticeably decreased.

A double infection of the larvae of Aedes flavescens and A. cantans with Thelohania opacita and larvae of Mermithidae was established. The double infection is not accompanied by the rise of pathogenic effect of the parasites on the hosts. Mermithids parasitizing mosquitoes infected with microsporidians inhibit the development of Protozoa. The inhibition degree depends on the duration of contacts of coparasites as well as on the developmental phase of microsporidians at the moment of penetration of nematodes.

Embryonal development of C. cirratus is described for the first time. The cortical activity at the first stages of cleavage has been noted. The extrusion of one of the polar bodies has been observed. The cleavage of C. cirratus is similar to the intermediate type, however there are some peculiarities. At first, the blastopore has a slit-like form, then Closes in the middle and thus two openings are formed. The "tadpole" embryo appears in 3—4 days. Hatching of the first stage larvae take place on the 10-th—12-th day after the cleavage starts. The description of it is given. The moulting occurs in water. The description of the second stage larva is also given.

The effect of antihelminth compounds on the cuticle, hypoderm and muscular cells of Ascaridia galli was investigated in vitro. Morphological changes were studied by means of light microscopy. The most pronounced changes in the musculocutaneous sac were found to be caused by santonin, hetrasan, piperasin and phenasal. Less effective are phenotiasin, naphtamon and enteroseptol.

The complexity and high cost of the existing methods of obtaining and preserving axenic cultures of Giardia (Meyer, 1970) have motivated the authors to look for new ways and means of simplifying the procedure. Solid media gave fair results which substantially simplified and accelerated the process and proved to be favourable for preserving the cultures longer without repassaging. Accordingly, the method recommended by the above authors facilitates the elimination of yeast from the cultures of Giardia in 15 to 24 days and the preservation of the axenic cultures over a period of 4 to 6 months without passaging, and within first two months at least the cultivation of new populations is guaranteed.

578 fleas of 16 species were found on 3518 animals collected in coniferous-broadleaved forests in the vicinity of the town of Izhevsk. Amalaraeus penicilliger, Leptopsylla silvatica and Hystrichopsylla talpae are most abundant. The main host of the fleas is the common redbacked vole. In addition to 15 species of the ectoparasites characteristic of rodents and insectivorous animals of this region Ceratophillus garei (a bird flea) was found on the common redbacked vole.

Summary is absent.

Summary is absent.

The dynamics of the distribution and concentration of toxoplasms of strain RH in organs and tissues of white mice infected subcutaneously was studied by the titration method during the toxoplasmatic infection. The distribution of toxoplasms in the organism was found to be active in the first 30 to 60 minutes with a subsequent fall of their concentration. In 24 hours no parasites were discovered by the bio-assay method. On the next days toxoplasms in the organs reached such abundance that caused the death of the animal. In the brain toxoplasms were found only after 3 days.

Data are given on the laboratory spontaneous occurrence of trypanosomiasis in young rats. It was demonstrated that the louse Polyplax spinulosa is the main mechanical vector of Trypanosoma lewisi. Unlike the case of the real host, the flea, the trypanosomes do not undergo the whole developmental cycle in the louse.

The parasite develops inside the fibres of the cross-striated musculature. On the histologic sections of the affected tissue most young stages of P. ladogensis are represented by 2—6 nucleic cells 5—6 µ in size. Mature pansporoblasts have a thick and solid membrane. Their average size is 43 (18—60) µ. The number of spores in pansporoblasts is over 16. Live spores are egg-shaped and are 5.4 (5.0—5.8)*2.9 (2.7—3.3) µ in size. The length of the polar filament is 100 to 180 µ.

A new species of endoparasitic nematodes, Meloidodera sikhotealiniensis, is described. The species was found on the roots of Betula mandshurica (Rgl.) Nakai and Spiraea sp. in the woods of the Primorye Territory. M. sikhotealiniensis differs from the close species M. floridensis by a small size of the body and the structure of the cephalic end of females, large stylet and long gubernaculum of males, thin digitate terminus of larvae. The new species differs from M. charis in an oval shape and size of the body of females, large stylet of females and larvae, low place of the entry of the dorsal duct into the oesophagal lumen, long and slender tail of larvae.

Summary is absent.

Summary is absent.

Summary is absent.

Summary is absent.