Shemot 8:14

להוציא את הכנים TO BRING FORTH GNATS — to create them and to bring them forth from some other place (not from dust but to turn some other material into gnats). ולא יכלו BUT THEY COULD NOT — for the demon (through whose agency this was to be done) is powerless in the case of a creature smaller than a barley corn) (Sanhedrin 67b). Therefore they had to admit,

וַיַּעֲשׂוּ־כֵ֨ן הַחַרְטֻמִּ֧ים בְּלָטֵיהֶ֛ם לְהוֹצִ֥יא אֶת־הַכִּנִּ֖ים וְלֹ֣א יָכֹ֑לוּ וַתְּהִי֙ הַכִּנָּ֔ם בָּאָדָ֖ם וּבַבְּהֵמָֽה׃

And the magicians did so with their secret arts to bring forth lice, but they could not: so there were lice on man and beast.