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The ultrafine structure of the Malpighian tubes in O. papillipes (Argasidae) was studied. It has been shown that the cells of different parts of the Malpighian tubes have their own peculiarities. The distal cells are characterized by the inclusions which can be interpreted as mucopolysaccharide ones. The main part of the tube was found to contain cells of two types. Most of the cells belonging to the first type have well developed microvilli and poorly developed basal invaginations. The cells of the second type, the number of which increases towards the proximal end of the tube, have small microvilli and narrow folds of the basal labyrinth entering deeply the cytoplasm. The cells of the second type are rich in mitochondria. The ultrastructure of the rectal sac has been studied. The cells of this organ have a polar structure: the apical surface is covered with microvilli, the plas-motic membrane forms deep folds at the base.

In the period from April to May and September to October of 1967—1973 in the Mujun-Kum a radioactive tracing of great gerbils was carried out. In all 225 tests were conducted. The greatest intensity of parasitic contacts between the animals was noted at their average quantity. Its further rise does not result in the increase of the parasitic relations. If the number of fleas is high the parasitic contacts level even at the relatively low number of great gerbils is usually high enough for a further passing of the plague microbe. If the number of both fleas and great gerbils is low the parasitic relations provide but not always an agent transmission.

The analysis of the landscape distribution of fleas from small mammals and birds in the southern taiga of Priirtishje is given. According to their abundance and faunistic composition the population of fleas from small mammals can be arranged into four groups: fleas of forest floodland landscape, those of forest—meadow floodland landscape, fleas of settlements and bogs.

In the valley of the Upper Yenisei IV instar larvae of Aedes vexans vexans were traced with ³²P and then 1.86 mln imagos were released. Among 442 857 mosquitoes caught after hatching 243 were traced. Most of the traced individuals did not yet start looking for prey and were caught during the first five days near the hatching site. 14 radioactive females were caught within 4.5 km distance from the hatching site in the following weeks.

Observations conducted over a period of 1960—1973 in the Uzbek SSR have shown that Ph. papatasi has two generations a year. The flight of sand flies in the oasis begins as a rule in the middle of May and lasts to the middle of September with peaks at the beginning of June and the end of July — beginning of August. Shifts in the main phenological dates in the same observation site are no more than two weeks. In desert territories situated southwards from the oasis phenological dates pass ahead those for the oasis for about 10 days. In localities with relatively stable conditions rather great variations in the abundance of this species (3—6 fold) from year to year were noted. In hatching places a tenfold increase in the number of Ph. papatasi was observed.

Materials are presented of a comparative study of morphological and cultural properties and virulence of liophylized cultures of Leishmania tropica major after their rehydration or after a long passage on the NNN medium. Results of investigations of two initial strains and three substrains obtained after the recovery of liophylized cultures have shown that liophylization does not reduce essentially the initial strain virulence. The strains undergone liophylization and passed repeatedly on the NNN medium have a tendency to a quicker virulence reduction rate as compared to initial ones. The culture of promastigotes recultivated after liophylization does not differ from the initial one in the ranges of 1—7 passages in its morphology, mobility and ability to grow on the NNN medium.

A new species of microsporidians, Thelohania jungarica sp. n., was described from larval populations of Odagmia sp. inhabiting the mountain rivers of the northern spurs of Tien-Shan, south-eastern Kazakhstan. The larval infection rate is 3 to 16%. The pupal infection was reported from single individuals. The species in question differs from other members of the genus in the morphology of spores, ecology and host. Sizes of measured 50 spores varied in the following ranges: live ones — 5.1-7.6 x 2.5-3.8, fixed and stained — 3.8-6.4 x 1.8-3.8 mkm. The parasite causes pathological and morphological changes in injured tissus.

On the basis of the analysis of regularities accompanying the secondary simplification of the life cycles of helminths on account of the reduction in the number of the animals— hosts 8 rules have been formulated. They are based on the following important regularities. 1. At the secondary simplification of the life cycles of helminths never fall out the first intermediate host in Trematoda and the definitive host in Nematoda. This phenomenon is suggested to be called "the host stability in the life cycle". 2. Mostly often from the life cycles fall secondarily out those hosts which join in the life cycle at its first complication later. 3. The phase of the helminth having transformed into a parasitic form at the first complication of its life cycle remains the same at the secondary simplification of this cycle.

The effect of procercoids of Triaenophorus nodulosus on the periods of metamorphosis, fecundity, survival and the capacity to infect Cyclops strenuus at all copepodid stages (I—V) was studied experimentally. It has been first shown that early copepodid stages (I—III) can be easily infected and serve as first intermediate hosts of T. nodulosus. Under the effect of the parasite the metamorphosis periods of the I and 2-nd copepodid stages increase considerably even at the low infection intensity while at the IV and V copepodid stages — only at the high infection intensity. If the infection takes place at the IV copepodid stage the female fecundity decreases even at a high infection intensity. The life span of infected and noninfected cyclops coincides. At early developmental stages the relations in the system "T. nodulosus—С. strenuus" manifest themselves in different ways and result in the breach of the important biological function of the host.

Some peculiarities of the biology of miracidia of Philophthalmus rhionica have been studied: penetration of the parasite's eggs into the environment, hatching of larvae, the miracidia motion, their life span and changes in the invasion ability character in time.

Minimum of the osmotic pressure in the intestine of the cod corresponds to the osmotic pressure of sea water of 10‰. The sorbtion level of neutral red by intact E. gadi remained practically unchanged after their maintenance in sea water of 8—10 to 30‰ during 24 hours (ecological optimum). Specimens of E. gadi transferred from 10 to 4‰ displayed compensatory recovery of the normal sorbtion level of the dye by the 5-th — 6-th day of the experiment. The ability of Acanthocephala possessing extreme eutelia to a physiological adaptation is indicative of its not obligatory participation of mitotic processes in the acclimation.

The paper presents literary and the authors own data. The potato stem eelworm Ditylenchus destructor has a set of chromosomes 2n=44—48 and does not cross with the close species D. dipsaci from onion, garlic, parsley and parsnip. Most stem eelworms of the collective species D. dipsaci have n=12 and cross with each other producing fertile progeny. Some forms of stem eelworms, e. g. those of broad beans, plantain, dandelion and falcaria are polyploid. Intraspecies and intrapopulation polymorphism according to the number of chromosomes was recorded. Some races do not cross, some cross but unilaterally, some races produce sterile, non- viable or little viable hybrids. The species D. dipsaci should be regarded not only as a complex of species but as a group of forms at different stages of intraspecies differentiation.

In the tarsi of all legs of Ixodes persulcatus, Dermacentor daghestanicus, Rhipicephalus turanicus and Hyalomma asiaticum the multicellular gland was observed. The gland is formed by a single layer of glandular cells that form a central cavity where two ciliary structures in a cuticular (scolopoid) sheath are situated. A possible function of the gland is discussed in the article.

In summer a series of experiments was conducted on the artificial infection оt Aedes caspius larvae. For infection were used suspensions prepared from larvae of this species, infected with the iridovirus. Experiments have shown that the agent can be used for the control of Aedes caspius under conditions prevailing in south-eastern Kazakhstan.

The finding of four 2-nd stage larvae and nine 3-d stage larvae of Hypoderma bovis on Tartarian roe is reported.

In freshwater fishes of North Viet-Nam were found representatives of the family Waretrematidae, Carassotrema koreanum and a new species of this genus, C. ginezinskajae sp. n., close to C. koreanum and differing from it in the structure and extent of yolk glands, relatively larger sizes of the pharynx and suckers, the location of spines and body shape. The described species differs from the other species of this genus, C. mugilicola, in the shape and location of testis, structure and location of yolk glands, intestine extent, size of suckers and pharynx, presence of cirrus, location of spines on the body and in other characters. Asymphylodora pavlovskajae Ha Ky, 1969 and Asymphylodora ginezinskajae Ha Ky, 1969 are reduced to synonyms of Carassotrema koreanum and C. ginezinskajae sp. n.

A new species of nematodes, Rotylenchus alpinus sp. n., is described. The species was found in the rhizosphere of Vaccinum uliginosum and Arctous alpina from the mountain tundra of Kamchatka. It differs from the close species R. orientalis in having a higher place of entering of the oesophagal dorsal gland duct, well developed hind ovary and in having males. From R. goodeyi the species differs by a lower place of entering of the dorsal gland duct, smaller sizes of the body and gubernaculum.

Summary is absent.

Summary is absent.