EN
Between 1963 and 1964, and again from 1964 until 1965, two research series were completed at the Warsaw Abattory to assess the incidence of Hypoderma larvae in the spinal canals of cattle. Each series of examinations of the spinal canals started October 1 and was completed Juli 15, next year. A total of 3673 spinal canals taken from slaughtered cattle aged one te five years, were examined. Following selected conclusions may be drawn from the results obtained: (1) Warble fly larvae were found in the spinal canals only between November 16 and June 30. (2) The highest incidence and intensity of invasion by the larvae occurred between January 16 and April 15. (3) Most larvae were recovered from the epidural fatty lining of the lumbar vertebrae. The larvae were less frequently found in the spines of the sacral and last thoracic vertebrae. (4) The present work fully confirms the geoclimatic specificity of the year seasons in which the warble fly larvae orcur in the spinal canals of cattle.