Zoological Institute of the Russian Academy of Science St. Petersberg, Russia Laboratory of Parasitology Introduction It is recognized that parasitological studies were initiated at the Zoological Museum in 1924 when a permanent Commission for the Study of Malaria Mosquitoes was established on the initiative of Academician E. N. Pavlovsky and Prof. A. A. Stakelberg. The Commission coordinated research of many beginner parasitologists. At the same time E. N. Pavlovsky and A. A. Stakelberg published a series of guides for the identification of mosquitoes and also methodical instructions on collection and examination of blood-sucking arthropods. In 1930, when the Zoological Museum was reorganized in the Zoological Institute, the Parasitology Division was established. The staff of the Division comprised E. N. Pavlovsky, the Head, and one technical-scientific worker. In 1934-1935 the Division was transformed into a Department consisting of two laboratories: Laboratory of Arachno-Entomology, its staff comprising D. I. Blagoveshchensky, A. S. Monchadsky and B. I. Pomerantsev, and the Laboratory of Parasitic Worms. In 1937-1940 the staff of the Department participated in an expedition of People's Commissariat of Health to the Far East. The purpose of the expedition was to study vectors of tick-borne and Japanese encephalitis. On the basis of data obtained during that field research and a comparison with data on a number of other diseases studied in Central Asia during many expeditions, E. N. Pavlovsky made generalizations of tremendous theoretical and practical importance, which have led him to the establishment of the theory of natural focality of transmissive diseases, i.e. diseases transmitted by insects and ticks. During WWII the Parasitology Department together with the entire institute was evacuated to Tajikistan, where its staff conducted a field research year round under conditions of Central Asia, which provided a great body of data for research. The limited number of research workers in the staff of the Parasitology Department could not conduct studies on all groups of practical importance. Therefore, leading specialists from other institutions were recruited for preparing volumes of The Fauna of the USSR series. Monographs and keys for the identification of sand flies (P. P. Perfilyev), horseflies (N. G. Olsufyev), blood-sucking mosquitoes and their larvae (A. A. Stakelberg, A. S. Monchadsky), blackflies (I. A. Rubtsov) and Mallophaga of domestic animals (D.I. Blagoveshchensky) were published by 1940 The Fauna of the USSR series. In the shortest possible time, the practical work in the areas of health service and veterinary medicine was provided with necessary up-to-date manuals that had been lacking in the USSR literature before. Based upon the generalization of ample new evidences, E. N. Pavlosky formulated in 1934-1937 an ecological concept of host's organism as a habitat of parasites and a theory of parasitocenoses. Advances made by scientific workers and an increase of the staff of the Laboratory after WWII resulted in publication of a number of volumes of The Fauna of the USSR series on the ixodid ticks and soft ticks (N. A. Filippova), feather mites (V. B. Dubinin), Mallophaga (D. I. Blagoveshchensky), mosquitoes (A. V. Gutsevich, A. S. Monchadsky, A. A. Stakelberg), biting midges (A. V. Gutsevich, V. M. Glukhova), on botflies (K. Ya. Grunin), on horseflies (N. G. Olsufyev), blackflies (I. A. Rubtsov), on sand flies (P. P. Perfilyev), synanthropic flies (A. A. Stakelberg). Keys to mites parasitizing on rodents (Ed. E. N. Pavlovsky), gamasid mites (N. G. Bregetova), and ixodid ticks (B. I. Pomerantsev, G. V. Serdyukova), lice (D. I. Blagoveshchensky) were published. In the 1960s research directions of the laboratory took a shape that have been retained in general up to present. In 2000 the staff of the laboratory includes 1 main research worker, 5 leading research workers, 3 senior research workers, 6 research workers, 1 technician, 3 collection curators, 3 engineers. In 1977 the Parasitology Department was reorganized in Parasitology Laboratory and a separate division for a study of parasitic worms was formed. Research is conducted by the laboratory in three directions. These are in particular ecological parasitology, fauna and systematics of parasitic ticks, mites, and insects and also morphology and physiology of parasitic insects and ticks.