Black and white sawfly

Black and white sawfly

Observation - Black and white sawfly. Description: This black and white chap was clambering over this Agapanthus which had quite a few white-fly-like insects on it. Distinctive markings unlike any in my field guide - very white under the abdomen (see pic 3) and striking facial markings with the white ring

This black and white chap was clambering over this Agapanthus which had quite a few white-fly-like insects on it. Distinctive markings unlike any in my field guide - very white under the abdomen (see pic 3) and striking facial markings with the white rings around the eyes in pic 1. As an idea of scale, the flower from petal tip to petal tip is about 30mm. Any ideas?