several trivittatus

several trivittatus

Observation - several trivittatus. Description: Good news, I've looked closely at the tops of the black pawn/chess-piece marking on tergite 3 this and the previous days' sightings and they're clearly all different individuals. An odd similarity though, a symmetrical dark nick about two-thirds up on the

Good news, I've looked closely at the tops of the black pawn/chess-piece marking on tergite 3 this and the previous days' sightings and they're clearly all different individuals. An odd similarity though, a symmetrical dark nick about two-thirds up on the yellow longitudinal thoracic stripes, pointing into the yellow from the black outer stripe, on all three flies. I started to wonder, do broods in particular places tend to carry similar markings? These look more-or-less like each other but not at all like Falk's illustration, for example

- included pictures 3 & 4 the previous two from the same thistle patch