Fucellia separata are another root-maggot fly on the sandy beaches. They are around the same size as F. rufitibia at 3.5mm to 6.5mm along with yellow cheeks. Their second and third leg are black in contrast to the rufous tibia of F. rufitibia, and their eyes are wider then they are high. They are uncommon but can be found in patches mainly in spring and summer months. They are consumed by arthropods and shorebirds. F. separata larvae consume kelp as well, but since they are in much fewer numbers, they don’t serve as important kelp removers like C. vanduzeei and F. rufitibia. Their diet, like other flies on the beach is relatively unknown, possibly consisting of fluids from kelp and bird feces or bacteria.