The biting gnat, C. variipennis was a vector of epizootic hemorrhagic disease (EHD) in white-tailed deer, Odocoileus virginianus, in Kentucky [USA]. Virus was isolated from parous females. Epidemiological evidence showed a close relationship of this vector to the animal host during an outbreak of EHD in penned deer. Larval breeding sites of C. variipennis were found and C. variipennis was the most abundant biting fly present during the outbreak. Females of C. variipennis were commonly observed biting deer, swine, cattle and occasionally, man.