Exodus 8:21

Swarms of flies] The nature of the pests is not indicated, as the Heb. word means simply 'swarms.' The LXX calls them 'dog-flies': cp. Isaiah 7:18. A general opinion is that they were beetles, of a peculiarly destructive sort. If this is correct, then the plague was again a severe blow to the religious notions of the Egyptians. The beetle was sacred, and was regarded as the emblem of the Sun-god. 'It was sculptured on monuments, painted on tombs, engraved on gems, worn round the neck as an amulet, and honoured in ten thousand images' (Geikie). A colossal figure of a scarabæus beetle is in the British Museum.