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Siphona boreata · dygliamusė

flickr.com/photos/63075200@N07/albums/72177720314614420/

It is a Palearctic species of fly. Body length 4-5 mm. Haustellum longer than the head height. Tergite 1+2 with strong laterals but no median marginals. Tergite 3 with 4 marginals. Tegula blackish. Knees of hind and usually mid femora darkened. Thorax with four pairs of postsutural dorsocentrals. Parafacialia narrower than a palp width (especially in males) with 3-6 setae at the top below the descending frontals. Head viewed from side about 1.5 times as high as long. Male with third antennal segment long (about as long as the length of the frons) distinctly widening towards tip where it is wider than a front femur, but segment shorter and narrower in females. Male abdomen with large lateral patches of yellow separated by a narrow dark vitta (less than one quarter width of tergite 1+2 but vitta broadening into a triangle on tergite 3. Females also have lateral yellow areas that can extend to tergite 3.