Flies rank alongside ticks and cockroaches as representatives of insect species that are hated by humans. This is probably because flies can transmit communicable diseases to humans.
However, compared to the time of EXPO '70, flies today are much diminished in force in urban areas thanks to a more hygienic living environment and improved sewer systems. Proof of this can be seen in the almost complete disappearance of fly paper, fly swatters, and other "fly countermeasures" in recent years.
In the time capsule are specimens of the common housefly and a relative of the green-bottle fly known as the hirozukin fly, a species seen all over Japan. (See photo.) Both were covered in plastic mold for storage in the capsule.