lesser bulb fly

Lesser bulb fly is a small to medium-sized hoverfly. It is native to Europe, Asia, North Africa, and the Indian subcontinent. It was been introduced into North and South America. Adults are found from April to September in dry grasslands, woodland edges, suburban gardens, anywhere their host species are found.

Larvae tunnel into plant bulbs, causing the bulbs to rot. The bulb either dies or produces stunted growth in the following growing season.

Adults are 3 ⁄16″ to ½″ long. The face is flat and covered with downward pointing hairs. There are two large compound eyes and three very small simple eyes (ocelli). The compound eyes are covered with hairs. On the male the compound eyes meet at the top of the head, and most of the head is covered with hairs. On the female the compound eyes do not meet and the hairs are parted on the forehead. The antennae are very short. The thorax is black tinged with bronze, with a fringe of pale hairs. There are usually two, sometimes three, pale longitudinal stripes, conspicuous toward the front, fading toward the rear. The plate between the abdomen and thorax (scutellum) is large and convex. It is colored like the thorax and has a fringe of long yellow hairs. The abdomen is black with a pair of gray or silvery-white oblique spots on the second, third, and fourth segments. The wings are clear and are covered with fine hairs. The second cell on the leading edge of each wing toward the tip (pterostigma) is tinted brown. The legs do not have spurs. The third leg segment (femur) is thickened.

Sources

24, 29, 30.

Location: Woodbury, MN