Flight period: May to July (occasionally also in April and August to September)
The very broad, flattened abdomen is characteristic making the insect appear “fat”. Both sexes have pale blue, thin ante-humeral stripes and brown eyes. The wing bases are very dark brown.
Male: quickly develop a blue pruinescence on the abdomen with yellow spots along the segment sides.
Female: golden brown on the abdomen, again with yellow spots at the margins.