Most calendars in Books of Hours show either sheep shearing or the wheat harvest for the labor of June. Some June pages instead depict the crab for Cancer and a scene from scripture. The June image from the Buchanan e. 3 ms. from the Bodleian, is a Book of Hours, Use of Rouen, in Latin and French
France, Rouen; c. 1500 for June is a typical June image.
There’s a peasant with a scythe on the top left, with the symbol for Cancer (though here the crab is more like a crayfish) on the bottom left. In the middle is the actual calendar, with the dates of various Saint’s days and other feasts that take place in June, localized for Rouen. The dates in blue are particularly important; traditionally these would be in red, in a rubric, giving use the phrase “red letter day.”
The Bibliotheque National NF, Lat 18104, fol. 3v, John of Berry’s Petites Heures, France, Paris 14th Century, for the month of June Shows Saint Paul preaching to the Philippians, the Church personified, and at the top, the symbol for Cancer, this time very clearly a crab.