Looks very similar to E. najas but is slightly smaller. Note the way the blue tail light slopes away forward on S8 to distinguish from its bigger cousin which has a more vertical front edge to its tail light.
[I have a comparison chart detailing the distinguishing features between E. najas and E. viridulum.]
- ♂ – red eyes
- ♂ – blue tail light slopes away forward on sides of S8
- ♂ – black X-mark atop S10
- ♀ – complete antehumeral stripes (cf. E. najas females)