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Studies of variability of the distribution parameters of the 2nd and 3rd stage larvae of Hypoderma bovis were conducted in the Soviet Union, Czechoslovakia and Mongolia. The co-variance analysis has shown that the parameters of regressions characterizing the changes in the exponent of the negative binomial distribution к remain constant in various parts of the area at different incidence of infestation of herds with H. bovis. This indicates that regulatory systems limiting the abundance of populations are associated with host-parasite relationships and do not depend on the complex of conditions specific for various natural zones.

The effect of meteorological factors on the flight to the light of Culicoides sinanoensis, C. sanguisuga, C. pulicaris and C. grisescens was studied in the valley of the Enisei river, 140 km from the town of Abakan up to the river. It has been established that the duration and intensity of the flight to the light are determined by the same factors as the duration of the biting period and abundance of biting midges though these types of activity manifest themselves at different time of the day: biting midges are most abundant in the morning and evening twilight while flying to the light ones are most abundant at night. Maximum flight to the light was recorded at the illumination less than 0 Lk, maximum biting activity — at the illumination of 250 to 1000 Lk. Ranges of temperatures registered at the flight to the light coincided with those registered during the biting activity period at the evening hours (the lower threshold for C. sinanoensis and C. sanguisuga — 8 to 9°, suboptimal zone — 9 to 12°, optimal for all four species — 12 to 18°) and were 4° higher than those in the morning that can be due to the sun radiation in the morning. To avoid a great error in the evaluation of changes in the abundance of populations counts conducted in the optimum zone of all meteofactors affecting the intensity of flight to the light were used.

Arguments are adduced in favour of conception of the polytypical species in the taxonomy of mosquitoes. In practice the main criterion of species is admitted to be morphologic cal one (its main four versions), which provides a possibility to identify individual specimens. Some widely distributed species are divided into subspesies, the distribution areas of which overlap sometimes throughout large territories. Areas which are co-inhabited by some subspecies are characterized by transitional forms.

33 species of fleas were recorded on Alticola (Platycranius) strelzovi Kastsch of which most abundant are Amphipsylla primaris primaris J. et R., Paradoxopsyllus scorodumovi Scalon, Sallopsylla gaiskii Vovchin. However, only one species, A. p. primaris, was found throughout the whole territory. Two species A. p. primaris and P. scorodumovi are capable of preserving and transmitting the infection due to these species often settle in dwelling houses.

Changes in the cellular contents of the haemolymph during ontogenesis of Alveonasus lahorensis have been first studied. The main types of haemocytes and their abundance ratio at all stages of the postnatal development and at various physiological states during feeding and moulting are described. The role of individual types of haemocytes in haematopoiesis and protective cellular reactions to a parasite and disease agent is discussed.

Observations with the use of microfilming and cytochemical investigations of haemocytes of Alveonasus lahorensis in the primary cell culture have enabled the authors to give morphological and functional characteristics of these cells. Morulashaped haemocytes as well as ctive mobility are characteristic of all the cells and determine only their functional staae. Mature haemocytes should be regarded as a type of the cells since the size of vacuoles tis a variable and cannot be used for classification, the more so that all vacuoles are sometimes dissolved and assimilated in cytoplasm.

8 species are reported for the fauna of cestodes of Sturnus vulgaris. Data on the incidence and intensity of infestation are given for each species and morphological descriptions are specified. Taxonomic positions of two species are revised. The shape of embryonal hooks of some species is placed emphasis upon.

As a result of the discussions it has been acknowledged in literature that there exist at least four separate forms of Trichinella in nature but not one. The opinions on the taxonomic ranks of the mentioned species differ: T. pseudospiralis is considered by some authors to be competent (except typical T. spiralis) while the species T. nativa and T. nelsoni are considered to be "strains" or "varieties". Others as well as the authors of the paper consider them to be distinct species because they differ in a number of characters the main of which is the absence of interbreeding.

A description is given and possible phylogenetic relations are discussed of seven earlier known genera and one new genus of microsporidians. A description of the new genus Neoperezia and the species N. chironomi gen. n., sp. n. from larvae of Chironomus plumosus is given. The new genus is characterized by unpaired nuclei at the most stages of the life cycle, the fission of sporont into two sporoblasts, prolonged junction of mature spores in two with plasmatic tubules. The new species is characterized by the presence of the membrane of pansporoblast around two spores.

Descriptions of four new Myxosporidia species, Sinuolinea schulmani (from dory), Alataspora lepidum (from sea robin), A. tetricum (from smear dab), A. serenum (from horse mackerel) and of two rarely occurring species, Coccomyxa morovi (from sardine) and Zschokkella hildae (from haddock and whiting) recorded from the Celtic Sea fishes are given.

A possibility of the introduction of the entomopathogenic fungus Coelomomyces iliensis in the south-eastern Kazakhstan was studied. Larvae of the mosquito Culex modestus were infected. Infectious substance (substratum, biomass and infected larvae) was brought from water bodies affected with the fungus. The infection of the larvae was conducted as in artificial pits (1 m²) so in natural water bodies (9 to 20 m²) with a density of larvae from 2720 to 9880 specimens per 1 m² of water surface. The mortality of larvae took place and infected individuals were observed. This suggests that in the investigated water bodies nidi of infection were formed.

The fixation of ticks of D. marginatus infected with tularemia in Carnua's fluid for 3 hours with their subsequent 10-day maintenance in 70° ethanol as well as their fixation in 70°, 80° and 96° etanol at a temperature of 4° and 20° to 22° С for 10 days excerts a bactericid effect upon the tularemia microbe in ticks that enables their safe hystological study.

It has been established that the vegetative stages of Myxosoma cerebralis actively phagocytate cartilaginous cells in addition to the fermentative delamination of the main substance of the cartilage. M. cerebralis is a typical anaerobe which provides itself with a considerable amount of carbohydrates. Drops of fat in the cytoplasm of Plasmodium are apparently a final product of anaerobic metabolism.

Midges (Cricotopus sp.) from Lake Tengiz (Central Kazakhstan) were found to be spontaneously infected (0.07%) with larvae of cestodes of Trichocephaloides birostrata Clerc, 1906. Sand pipers Calidris testacea (2 of 5 dissected) and Calidris minuta (one of 7 dissected) from the same water body were also infected with this cestode. Figures and morphological description of cysticercoids and mature specimens of Trichocephaloides birostrata are given.

A new species of nematodes found in the rhizosphere of Leontopodium fedtschenkoanum Beauverd in the belt of the spruce forest of North Tien-Shan at the height of about 3 thousand metres above the sea level is described and figured.

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