The necessity of mandibles for ID - Osmia

For the pinned Osmia I usually see, the mandibles are closed and features obscured. A major issue for Osmia, because mandibles are key in the keys. Going forward, I will mount Osmia with a mandible exposed. That is hard to do without popping off the head, which I will look for under my desk, only to find that there a number of bee heads to sort through. A good work-around if you have a series of one species: crush the head of one of the extras, and glue the head+mandibles to a separate pin.

Photo links here: The mandibles of an Osmia which tell me:

• Polygonal shape;
• Parallel basal ridges, of equal size;
• Cutting edge not differentiated from upper tooth;
• Ratio of margins of lower and next tooth

anterior view, and lateral view

Posted on August 24, 2022 05:30 PM by cappaert