Photo by Alfredo Colon

Eumerus is a genus of small hoverflies in the family Syrphidae. With 281 known species, it is one of the largest genera of flies. It is found throughout the Palearctic realm, which includes Europe, Asia north of the Himalayas, North Africa, and the northern and central parts of the Arabian Peninsula. Several Eumerus species have been introduced into North and South America. Three of these are known to occur in the United States: lesser bulb fly (Eumerus funeralis), narcissus bulb fly (Eumerus narcissi), and onion bulb fly (Eumerus strigatus). Collectively, they are known as lesser bulb flies.

Adult lesser bulb flies are black tinged with bronze. They have pale longitudinal stripes on the thorax and silvery-white stripes on the abdomen. The larvae are considered pests. They tunnel into plant bulbs, causing the bulbs to rot. The bulb either dies or produces stunted growth in the following growing season. In some areas, up to 25% of narcissus bulbs are infected.

http://www.minnesotaseasons.com/Insects/lesser_bulb_fly_(Eumerus_spp.).html