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The parasite fauna of Coregonus peled, C. autumnalis migratorius, C. lavaretus, C. albula, Salmo irideus and Ciprinus carpio was investigated. Ciliata and Diplostomatidae were found to be most abundant. The paper discusses the effect of certain factors (the character of a water body, food, mode of life of fishes) on the parasite fauna of fishes introduced to small lakes of Karelia.

The spring Chilu-Chor Chashma (forty four springs) is situated in the south of Tadzhikistan. In this water body water temperature is constant in any season of the year (18 to 20 C). Ichthyofauna is represented by three species: Varicorhinus heratensis natio steindachneri, Alburnoides bipunctatus eichwaldi and Cyprinus carpio. As a result of parasitological studies 20 species of parasites were recorded from 129 fishes. The parasite fauna of the fishes was investigated twice — in summer and in autumn. It was found that in autumn it is much poorer than in summer. This concerns mainly the species with a complex developmental cycle.

A new species belonging to a new genus of Monogenoidea was found on the gills of Euleptorhamphus viridis from the Indian Ocean. The opisthohaptor of the new genus consists of two medially overlapping rows of clamps situated on a double fold along the oblique posterior margin of the body. Clamp are of Microcotyle type, their springs having accessory pieces. Three pairs of larval hooks are present. The genital atrium is armed with three groups of spines. The first group comprises spines surrounding the female aperture; the second one surrounds the cirrus in an incomplete circle; the third group consists of two lateral groups of spines arising from two muscular pad-like structures. Vagina armed with a chitionous spine opens on the right-hand side which is longer than the left-hand one. Behind the U-shaped ovarium vitellaria merge in an undifferentiated mass and completely cover the branches of the intestine and the testes. The new genus is close to the genera Chlamydaxine Unnithan, 1957 and Axine Abildgaard, 1794 differing from the former by an armed genital atrium and from the latter by two medially overlapping rows of clamps.

Different strains of Hymenolepis nana from man, Norway and white rats were studied in regards to their adaptability. Strains obtained from spontaneously infected white mice and those passaged for several years on white mice served as control. In the course of successive passages the infectivity of these strains, developmental rates of tissue larvae, localization of cystocercoids in the small intestine and mesenteric lymph glands were compared. The strains were found to possess different adaptability to white mice. The strain from white rats had the highest rate of adaptation, the strains from Norway rats and man showed lower adaptation rates, respectively.

Cyathocotylid larvae were found in the musculature of Gobio gobio and Leuciscus leuciscus from the cut-off part of the Ishim river (West Sibiria). Experimental infection of domestic ducklings has shown that the metacercariae are the larvae of Cyathocotyle prussica. They differ from the other known larvae of Cyathocotylidae from musculature of fishes of Europe and Asia in having a larger Brandes' organ.

There has been no information on cystogenous nematodes of the genus Heterodera injuring apple trees. The paper checks the first finding of these nematodes on the roots of a cultivated apple tree. The nematodes proved to be a new species, Heterodera mali sp. n. The apple cystogenous nematode resembles the potato cystogenous nematode H. rostochiensis Woll. in having a round body, small cleft of the vulva and similar sizes of eggs. It differs from H. rostochiensis in smaller sizes (on the average 5 against 9) very transparent and thin cuticle, a small distance between vulva and anus (on the average 43 against 86), a smaller value of the Granek's index (on the average 1.3 against 4.6), a smaller number of cuticular folds between vulva and anus (on the average 7 against 21) and different plant-hosts. A detailed description of H. mali sp. n. is given.

Ixodes caledonicus differs from the most allied species I. berlesei at all active phases of its life cycle. In the USSR I. caledonicus is distributed in the Ukraine — in the Crimea, on Tarkhankut and Kerch Peninsulars, in Azerbaijan — in the south-eastern spurs of the Great Caucasian ridge and in the midcourse of the river Araks, in Tadzhikistan — on the southern slope of the Gissar ridge. The species is reported from Great Britain, Sweden, FRG and Poland. I. caledonicus belongs to a nest-burrow type of parasites, is recorded from mountain and elevated regions, lives in rocks. Birds nesting in rocks serve as its hosts. Differential (as regards I. berlesei) diagnoses of female, nymph and larva are given.

Data on the distribution and ecology of Ixodes trianguliceps in the South Urals are presented. This species occurs in various landscapes of the forest zone of the South Urals between 52°11' and 52°22' N. lat. It infects 9 species of small mammals of which species of the genus Clethrionomys were found to be the major hosts of I. trianguliceps in this area.

Results of the experiments have shown that the development of Dermacentor silvarum from egg to imago varied from 44 to 46 days at 28° С and redundant humidity and from 50 to 52 days at 25° C. The thermic threshold of larval development lies within a range of 8.6° C, that of nymphs — 9.7° C. A sum of effective temperatures required for larval development averaged 123.5° C, for nymphs — 225° C and for the whole ontogenesis — from 570 to 690° C. In the north of the distribution area of D. silvarum this species seems to occur only in those localities, where a sum of effective temperatures is higher than 10° C and makes not less than 570° C.

Laboratory studies have shown that at 75% humidity fleas, Ctenophthalmus wladimiri, are less viable than at 100% humidity. At 100% humidity at a temperature from 0 to 10° and without feeding newly born imagos survived up to 363 days, at a higher temperature from 18 to 30° — from 44 to 163 days. At a temperature from 7 to 10° imagos, which fed one time, lived up to 355 days and at 0 to 2° — up to 287 days. Maximum life duration (1133 days) for periodically feeding fleas was at 100% humidity at a temperature from 7 to 10°. Under such conditions 50% of fleas survived up to 114 days. Hungry but previously "prepared" for winter fleas lived at a temperature from 0 to 2° not more than 376 days.

Some data on the fauna of louse-flies of migratory birds are presented. An ecological analysis of the distribution of louse-flies species on birds of passage during their spring and autumn flights is also given.

Six species of mosquitoes were recorded from the settlements in the oasis zone of Turkmenia. In all the settlements Phlebotomus papatasi was prevalent, in the burrows of foxes and great gerbils Ph. papatasi was most abundant and in the burrows of midday gerbils Sergentomyia arpaklensis was most frequently encountered. Epizootological investigations testify to the possible cases of cutaneous leishmaniosis within the oasis that is associated with intraoasis natural foci of zoonosal cutaneous leishmaniosis. These foci are potentially dangerous. In years of mass reproduction of gerbils and other wild animals, infection reservoirs, at high abundance of mosquitoes a danger of infection of population with cutaneous leishmaniosis cap arise in such zones.

Two new species of microsporidians are described from the mosquitoes of the genus Chironomus collected in water bodies of the north-eastern USSR. Bacillidium chironomi sp. n. injuring the adipose tissue of the fourth stage larvae of Chironomus dorsalis Mg. has rod-shaped spores 15 (11 to 19) X 0.7 (0.6 to 0.9) µ in size. Duboscqia chironomi sp. n. injures the adipose tissue of the fourth stage larvae of Chironomus plumosus L. Fresh spores of this species are egg-shaped, 6.2 (5.8 to 6.5) X 3.8 (3.6 to 4.0) µ in size. When stained according to the Romanovsky-Gimza method the spores are 5.4 (4.9 to 5.8) X 3.8 (3.6 to 4.1) µ in size. Some peculiarities of the nuclei fission in the sporants of Duboscqia chironomi sp. n., are discussed.

Two new species of the genus Apiosoma (Peritricha, Sessilia) are described: A. constricta sp. n. from the body of the perch and A. tenera sp. n. from this year brood of the carp. The new species were found in ponds and lakes of the Chelyabinsk and Sverdlovsk districts.

Summary is absent.

Summary is absent.