The Alfalfa Leafcutting Bee (Megachile rotundata) is a small insect in the Megachilinae sub-family of solitary, leafcutter bees. 

The Alfalfa Leafcutting Bee has a slightly flattened, elongated, shiny, dark-grey to blackish body. The female has white hairs all over her body. The male has white and yellow spots on its abdomen. It has six legs, two pairs of wings, and three body parts: (1) head, (2) thorax, and (3) abdomen. Its wings are translucent (see-through). It has a stinger, but it is generally harmless to humans.