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Photo#15770
Goldenrod Gall Fly - Eurosta solidaginis - male

Goldenrod Gall Fly - Eurosta solidaginis - Male
American Tobacco Trail south of Scott King--power line right-of-way, Durham County, North Carolina, USA
April 25, 2005
Size: 7 mm
The galls I have kept under controlled outdoor conditions over the winter have finally started to yield a few flies. The first few to emerge have been males, and they have taken up positions on the top of the goldenrod stems. They are rather sluggish, and, being careful, I was able to take individuals out of the batch for photography. In some cases they flopped down onto the countertop. I was able to coax this one onto a foam pad as a background for photography. Compare the wing pattern to the somewhat similar Delphinia picta:



The Eurosta does perform a bit of wing-waving while walking, though not as much as Delphinia. Size of the Goldenrod Gall Fly was measured by photographing adjacent to a scale, and is the approximate length from head to abdominal tip. This is a male, based on the lateral image showing male genitalia, not a long ovipositor, as shown on the Eurosta Page

Having seen the sluggish nature of these flies after emergence, I'd be very hard-pressed to find one in the wild. They apparently emerge and take up a stationary position until mating.

Images of this individual: tag all
Goldenrod Gall Fly - Eurosta solidaginis - male Goldenrod Gall Fly - Eurosta solidaginis - male