RESUMEN
With the purpose of studyng the seasonal variation and the population increase of Dermatobia hominis group's in bovines, the verification of nodes distribution caused by the grubs in the host's body area as well as the relationship between the quantity of D. hominis groups and the weather information, 79 rural properties in Santa Maria city were visited. In each property 10 animals were selected that were individually inspected. Results indicated that the highest parasitism numbers occurred during the warm months (from October to February). On the other hand, during the cold months (from April to September) the infective rates were lower or even none. Concerning the body areas, the front part showed 83,3 per cent of the nodes, while the back one presented just 16,4 per cent of them.