Aspects of the reproductive biology of some cattle-visiting Muscidae (Diptera) in north-east England.

During studies of flies that visit farm animals in north-east England, samples of Muscidae were obtained on a regular basis from grazing animals (mainly cattle) and from Manitoba traps. Female flies were examined to determine their wing length, degree of wing damage, whether or not they had mated, whether their crop or gut contained blood, the stage they had reached in ovarian development and the number of eggs present. This information was used to assess the timing of mating, the stage at which blood meals were taken and the potential fecundity of the more numerous species, especially Hydrotaea irritans (Fallén) and Morellia simplex (Loew). A relationship between the size of the individual and the number of eggs it carried was found in several species.