Quinisext Council, Canon 42.
As touching so-called hermits, who dressed in black and with a growth of hair on their head go about the cities and associate with laymen and women, and insult their own profession, we decree, if they choose to tonsure their hair and adopt the habit (or garb) of other Monks, that they be installed in a Monastery and be enrolled with their brethren there. But if they do not prefer to do so, they must be driven out of the cities altogether and be forced to dwell in deserts, from which they formed the name they have applied to themselves.
Because of the fact that of old many deceivers of the people calling themselves hermits, wearing black and growing hair on their head, roamed round cities, mixing with men and women, and discrediting their monastic profession, the present Canon decrees that if such men are willing to cut off their hair, like the rest of monks who live in monasteries, and to be settled down in a monastery, well and good; but if they are unwilling, let them be driven out of the cities entirely, and let them go and dwell in the deserts, from which they falsely, and not truly and truthfully, came to call themselves “hermits.” (Note of Translator. — This word hermit in English has somehow or other acquired an initial h which does not belong to it. It is derived from the Greek word for desert eremia, whence the Greek word in question is eremites, meaning “(a monk) inhabiting the desert or wilderness.”)
 Note from the present Canon that monks living in monasteries and coenobitic communities must cut their hair symmetrically; for it appears that monks affect a symmetrical haircut both from this Canon and from the discourse of Athanasius the Great concerning virginity, and also from the first sermon on Peace by St. Gregory the Theologian, and from many historical narratives of Lausaicus. Since the present time is (considered to be) a time of mourning among monks, according to divine Chrysostom (Homily on the Gospel of St. Matthew No. 56) and John Climax. God, by the way, says through Isaiah that shaving the head is a sign of mourning and weeping and of beating the breast (Isa. 22:12). And if, as St. Paul says, any man in general is ugly when he has hair (and see the Footnote to c. XCVI of the present (C.), how much more ugly monks are who grow hair! But if all monks in general ought to cut their hair symmetrically, how much more ought young monks living in monasteries or cells, and deacons, to cut their hair! For such persons scandalize others with their beardless face as much as they do with their long combed hair. Against these incongruities those living in cities, and especially those living in the imperial capital city ought to be on their guard at all times.http://jbburnett.com/resources/canons/56can/56can042.html