To start to differentiate between the species of Sympherobius, firstly look at how many branches of R are present (see below image). Two branches will give you the species Sympherobius elegans and S. pygmaeus (click here), three branches will give you three species S. fuscescens, S. pellucides, and S. klapaleki (click here).
For species with two branches of R there are a few features that can help you to identify the species, such as thorax stripe, wing pattern, colour of veins, and the male genitalia (see below image).
For the species with three branches of R, have a look at the colour of the antennae to see if the scape and pedicel (first and second segment) are the same colour as the rest of the antennal segments (see below image). If they are see below image, if the scape and pedicel are a yellowish colour and the rest of the antennae is dark click here.
The third species Sympherobius klapaleki, differs from S. fuscesens and S. pellucides in having a pale yellow scape and pedicel, with the rest of the antennae being dark (see below image).
