The days of Apelles are now past, and our Modern Painters are quite of another strain from these old Masters, who never came to be considerable in their Professions, but by the study of Geometrie and Perspective, the Anatomy of Bodies, and the assiduous Observation of those Characters which expres’d the Passions and Emotions of the Soul; by the lecture of the Poets and good Historians; and in fine, by a continual re-search of whatever might best contribute to their Instruction.

(An Idea Of the Perfection of Painting, sigs. A3r–v)

[Artists] were in those days so Docile and Humble, that they not only would submit their Works to the Criticismes and Animadversion of Scholars and Philosophers, but even to the Common People also, and to Artificers of all Trades, who did frequently and sometimes judiciously reprehend them.

(An Idea Of the Perfection of Painting, sig. A3v)

Pliny has recorded of Apelles; who before he gave the last touches to his Pieces, was wont to expose them in Publique to the Censure of all the Passengers, whilst he conceal’d himselfe behind them, that he might hear what every one said, and make use of it accordingly; whence the Proverb, Apelles post Tabulam.

According to Horus Apollo, the fly was the most ancient symbol for impudence, because these persistent little pests, “when driven off, will nonetheless fly right back.”
     Why did the great masters of early Netherlandish realism, and later of the Italian Renaissance, devote loving care to such an unlovable creature as the fly? In a positive way, these painters earned the same title as the Bible’s Evil One, Beelzebub, Lord of the Flies. By adding these tiny insects to their pictures, using brilliant illusionism, a painter could fool the viewer into accepting his artifice for the work of God, and so take on almost magical powers. These insects’ presence proves that their artists had read Pliny, whose Natural History describes how Apelles painted a fly so skillfully that all who saw it sought to brush it off. While Dürer was still an apprentice in Wolgemut’s studio, he was said to have painted a very realistic fly on the brow of the archangel in his master’s picture of the Annunciation. Unable to whisk the insect away, Wolgemut caught on that Dürer was the real pest.
     On his first visit to Venice, Dürer was certain to have seen Cima da Conegliano’s recently completed Annunciation (1495) for the Church of the Crusaders, where a fly looks as though it has just landed on the canvas. It was placed there to call attention to the artist’s name, inscribed on a little piece of paper which, like the fly, seems also to have happened upon the surface by accident.
     In 1504 Dürer included a large, mean-looking horsefly in his Adoration of the Magi; two years later, back in Venice, he painted another one resting on the white cloth of Mary’s dress in his great altarpiece The Feast of the Rosegarlands, known today from a copy. There, the fly is a sign of death as well as art. After all, the fly was known in Latin as Sarcophaga canaria, or meat eater, and described in von Megenberg’s Bidpai: The Book of Nature as a harbinger of Christ’s death and sacrifice.
     Dürer had a personal reason for giving this fly such prominence. Of the many portraits he included in the painting, mostly of members of the German traders’ company in Venice, those placed closest to the Virgin and the fly are the two most powerful — the pope and the emperor, whom Dürer hoped to impress. Just under Maximilian’s Habsburgian beak, the fly is shown in actual size, while all other figures are reduced by half; we can be sure it was meant to be seen as a living, breathing work of life, not art. Doubtless Dürer wanted to identify himself with Apelles, court painter to Alexander the Great, and be given the same role by Maximilian.

Dürer here prefigures the microscopists’ fascination with interdependencies of scale, in time and space. The mayfly lives a full life in so short a period of time that it is popularly known as “the one-day fly.” In Dürer’s work The Holy Family with the Mayfly, only the mayfly, along with the Virgin and baby Jesus, is awake to the sacred presence of the divine (as God the Father and the Holy Spirit appear to the Mother and Son, while Joseph sleeps in the left of the picture). The mayfly also serves here as a pointer to the brevity of Christ’s life, on the human scale. (from Colin Eisler 1991, p. 130)