Two species of the blow fly, C. nigribarbis and A. graham, are categorized as larger-sized fly species in particular in comparison to the house fly Musca domestica (L.); its body size is 5-8 mm (Figure 2 ). The body length of female C. nigribarbis is 11-15 mm and approximately 1.5 times larger than that of female A. grahami (8-13 mm) . The capacity of the crop of female C. nigribarbis (average = 23 mL) is approximately five times greater than that of female A. grahami (average = 4.4 mL) [11] . The consumption rate of both C. nigribarbis and A. grahami might have been high because of their large body size. In fact, virus genes were found more often in C. nigribarbis than in A. grahami [11] . Stable flies, Muscina stabulans (Falle'n) and M. angustifrons (Loew), collected at the same collection sites and the same time as the fly surveillance in Kyoto, showed much smaller body size than C. nigribarbis and A. grahami, and no virus was detected in these smaller-sized flies [11] .