Fly, Louse, and Flea in Religion, Myths, Mythology and Folklore

In the biblical book of Exodus, the fourth plague sent by Yahweh when the pharaoh refused to release the Israelites was a plague of gadflies that filled the palaces (8:1-20), a particularly insulting punishment since these insects are generally attracted to cattle. The Egyptians, however, seem to have admired the appearance of houseflies, which they frequently used in decorative pins. Pendants of gold in the form of flies were awarded to soldiers for valor. In the play Prometheus Bound by the Greek tragedian Aeschylus, Hera changed the maiden Io into a heifer as punishment for having an affair with Zeus. Then the goddess sent a gadfly to drive the unfortunate creature across Europe and Asia. A similar image is used, though in a positive way, in Plato's “Apology,” where Socrates compared himself to a gadfly sent by God to prod the Athenians out of their complacency. In a similar spirit, the Greek poet Melegros called upon a mosquito to buzz in the ear of his beloved to remind her of his love. In many cultures, especially in East Asia, insects have represented the soul. In Journey to the West, a mythological epic written by Wu Ch'eng-en in late medieval China, Old Monkey sometimes took the form of a fly to escape from demons or to elude detection. Among the Montagnards of Vietnam, fireflies have traditionally been considered the spirits of departed heroes. In Japan and China, fireflies are the companions of impoverished scholars engaged in nocturnal study. Because they provide moments of illumination, short poems written on fans or pieces of silk have been known as fireflies.

The name of the demon Beelzebub, originally a Phoenician deity, literally means Baal of the Flies or Lord of the Flies. In the Old Testa ment, Beelzebub tempted King Ahaziah of Israel away from Yahweh (2 Kings 1:2-6), and later he was called the “prince of devils” (Matt. 12:24; Mark 3:22; Luke 12:15). In the Christian Middle Ages, demons were frequently depicted as flies, and so people often thought of swallows and other insectivorous birds as holy. There are several stories of devils taking the form of insects to enter the bodies of people by mouth. According to a local chronicle, for example, in 1559 a maiden in the Harz Mountains near Joachimsthal inadvertently swallowed an evil spirit, disguised as a fly, in her beer. The demon immediately possessed her and began to speak through her, though it was finally exorcised by the parish priest.

Before improvements in hygiene in the modern period, lice could be found in the hair and on the body of nearly everybody, from king to peasant. Though a perpetual annoyance, they could also serve as a means of social bonding. To pick lice off a person was a service that might be performed by parents for children or servants for masters. It was even a ritual of courtship and love, performed by couples. The presence of an inordinate number of lice might indicate either coarseness or, for ascetics, a lack of worldly concern. Thus, Julian the Apostate, the austere Roman emperor who attempted to revive paganism, once compared the lice running freely in his beard to wild beasts in a forest. Fleas also tended to be thought of in a familiar and, at times, even affectionate way, though they were by far the most dangerous insects of the lot. Though it was not realized until the end of the nineteenth century, fleas had been carriers of many diseases, including bubonic plague. In the Renaissance, references to fleas became a humorous convention in poetic diction. Among the most famous examples is “The Flea” by John Donne, a poem in which the author requests sexual favors from a woman by showing how their blood has mingled in the body of a flea:

But insects, like rats, are now often put in the service of medicine. Apart from human beings and perhaps rodents, the drosophila fruit fly has become the most studied animal in the world. Scientists have found that the genetic code of the fruit fly is easy to manipulate and has many affinities with that of human beings. In hope of correlating them with parts of the genome, all features of the creature's life, from anatomy to courtship dances, have been intricately observed. One journalist recently remarked that researchers who study fruit flies “are easily provoked into confessing that they think of people as large flies with wigs” (Wade, p. F1)