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For 13 species of horse flies distributed in the middle zone of the European part of the USSR are given habitats of larvae and data on density of their population. In the Voronezh region the density of population ranged on the average from 1.2 (floodland meadow) to 12.5 (ponds) per 1 m². Data on the seasonal occurrence of larvae and their rearing to imago suggest the facultative two-year life cycle in Tabanus bovinus Lw., Hybomitra tropica Pz. and Haematopota pluvialis L. The problem on the possibility of estimation of the number to hatching horse-flies over the whole area of the biotope is discussed.

Studies on 29 species of larvae of the genus Culicoides and analysis of the literature have permitted the author to give a comparative-morphological description of the larvae of this genus.

Studies were carried out on the feeding rate and the volume of engorged liquid in Xenopsylla gerbilli minax and Ceratophyllus laeviceps under the conditions of compulsory feeding through a capillary. The feeding rate and the volume of liquid engorged depend on the quality of food: if blood from other animals was added, a marked rise in these values was observed. Observations were also made on the survival of compulsorily infested fleas and the vitality of microbes of plague in them. It has been established that the compulsory feeding does not cause the increase in the mortality of fleas and that the fleas infested with microbes can make themselves free of them.

The Gamasina are of particular interest to the parasitologist because the range of extant forms permits examination of many intermediates in the acquisition and evolution of parasitism. Nest-dwelling is important in the establishment of the parasitic relationship. Pressures relative to mating are involved in the tendency to concentrate in nests, and the characteristics of a non-parasitic nidicole may closely preadapt the species for parasitism. To determine relationships between parasitic groups, greater emphasis is now being placed on post-embryonic developmental patterns, particularly with regard to the activity or quiescence of preimaginal stages. The many forms that intergrade between groups also contribute to understanding the phylogeny. Changes in the life history are associated with the particular needs and capabilities characteristic of the parasite. Certain quiescent stages appear to function analagously to the insect pupal stage. Various structural modifications are considered in relation to their parasitic functions. Chelicerae of Dermanyssidae are specialized to act in a similar manner to the fascicles of some haematophagous insects.

In the trombiculid fauna of Azerbaijan there were established 58 species representing 16 genera. In more ancient parts of land (in mountainous part of Great and Small Caucasus) the fauna has the most peculiar individual character: the former has 13, the latter — 14 species of Trombiculidae occurred only in the limits of corresponding geographical area. Community of trombiculid fauna of highland steppes of Small Caucasus and Talish is being watched. The main part of fauna of the geologically youngest Cura-Arax lowland is composed by species discovered in mountains of Great and Small Caucasus, and Talish with only three particular inherent species.

The paper presents an analysis of the occurrence of Ixodes trianguliceps on different species of hosts and its distribution depending on zonal-climatic conditions in Karelia.

The paper contains descriptions of a new genus Triacanthinella (Dactylogyridae, Ancyrocephalinae) from the gills of marine fishes of the genus Triacanthus (Triacantliidae) and of five new species belonging to this genus (figs. I, 5—9). The authors indicate that the species Ancyrocephalus triacanthi Tripathi 1957, whose redescription seems worth while, belongs to the same genus. The genus is characterized by a complex apparatus of the haptor consisting of huge anchors, connective bars and a strongly developed system of muscles. The structure of this apparatus and its mechanics are described in detail. Fig. 3 shows the haptors of the worm attached and non-attached to the gills. Fig. 4 shows a scheme of association of chitinoid parts and musculature of the adhesive apparatus. The type of the adhesion in worms of the genus Triacanthinella differs from that in other Ancyrocephalinae by special associations of dorsal and ventral anchors lying in one plane and forming two clamps along the lower edge of the haptor and by a springy effect of the ventral bar. The analogous function of the adhesive apparatus in its separate links is observed in some lower Monogenea, particularly in Diplectanidae. There is a certain similarity in the function of the adhesive apparatus in Triacanthinella and bianchoral forms. Thus, similar relationships are observed in Dogielius, whose two anchors with their points turned towards each other lie in the same plane and are operated by a springy connective bar as well as in Triacanthinella. It is, however, only a very approximate analogy.

Didymosphaera mirabilis gen. et sp. nov. found in the frigate mackerel in the North Viet-Nam Gulf in 1960 is described. Trematodes, which live in the cysts, consist of two firmly joined together hermaphroditic individuals. They have two filamentous forebodies and one globular hindbody. In the latter there are two sets of intrenal organs, which apparently function independently but are closely interlaced and united by the common parenchyma. The above trematodes are characterized by strongly developed metraterms and egg reservoirs, which occupy the middle part of the hindbody. They are related to Colocyntotrema, Opepherotrema and Didymocystis.

A new species of trematodes was (Lepidophyllum schantaricum sp. n., fam. Steganodermatidae Dolff., 1952) found in the urinary bladder of Zoarces viviparus elongatus caught in the middle horizon of the intertidal zone of the Jakshin gulf (Great Shantar Island) in August, September, 1966. A new species differs from other species of this genus in a shape of the body, in a shape and size of intestinal branches, in the presence of a very short oesophagus and the location of genital glands.

The infestation of domestic and wild animals (Siberian polecat, fox, corsac fox, dog, cat and Norway rat) with trichinellids was recorded throughout the Semipalatinsk district.

A study of helminths from birds of prey during various seasons in Azerbaijan has revealed their dependence on changes in food, the abundance and species of the I^st intermediate hosts and migrations of birds. The fauna of helminths in various birds is formed on account of the quality of food consumed. In birds with a narrow specialization to food monotonous diet makes the fauna of helminths poorer. At the same time the frequency of consuming infested animals is higher than it is in less specialized birds, in which the fauna of helminths is richer due to diversity of food consumed. The feeding of birds on animals unusual for their diet depends on the abundance of the latter; due to this the parasite can develop in the non-specific host that enlarges the range of hosts.

The effect of larvae of trematodes (Notocotylidae, Echinostomatidae, Plagiorchidae and Cyathocotylidae) on reserves of cardiolipins and their topography in tissues of the digestive gland of freshwater gastropods (Limnaeidae, Planorbidae, Viviparidae and Hydrobiidae) was studied. Studies of sections have shown that reserves of cardiolipins noticeably decrease in the digestive gland of mollusks invaded with larvae of trematodes.

The effect of various temperatures on the development of Nuttallia tadzhikistanica in Hyalomma anatolicum was studied. It has been established that a short exposition (from 2 to 48 hours) of ticks infested with nuttallians to low temperatures (from 0 to 6°) does not exert a damaging influence on the latter. At temperatures from 15 to 22° nuttallians complete their development in Hyalomma anatolicum without reaching the invasional stage. During the cultivation of ticks infested with nuttallians from 12 to 144 hours at 35 and 40° the greater part of ticks did not transmit nuttallians to their vertebrate host.

Summary is absent.

Summary is absent.

Summary is absent.