The features shown in this image are diagnostic for Bembix palmata males. The bright yellow clypeus is concave apically, has prominent round lobes laterally (curved solid arrow), and has a small median, basal ridge (star). The labrum is depressed near the base (dotted arrow), and also bright yellow. And the shape of the extremely broad front basitarsus (straight arrow) is unique.

Bembix palmata

Image courtesy Reiner Richter
https://inaturalist.ala.org.au/observations/147447501

The best chance to see the sternal process of males is when they are feeding at flowers. This species has a high ridge on S2, right-angled at the apex (straight arrow).

The yellow marks on the sides of the propodeum (curved arrow) are also visible from this angle. Note too the yellow marks on the extreme lateral sides of T1, highlighting the extent to which the dorsal tergites wrap around ventrally.

Bembix palmata

Image courtesy Reiner Richter
https://inaturalist.ala.org.au/observations/147447501

Although the diagnostic features in females of this species are not as pronounced as in the male, they are nevertheless enough for a species ID (when taken in combination with colour patterning).

As in the male:the clypeus is broad with a median carina basally (star); the labrum is depressed basally (dotted arrow); and the front basitarsi are expanded (solid arrows) as are the following tarsomeres.

Note too the vertex level with the eye tops (line). This is the not an uncommon condition, but it does contrast with some other extensively yellow species such as B. flavifrons.

Finally, in this species the female typically has a pair of black spots on the yellow clypeus. This too is a widespread pattern, seen in many species (yet often highly variable within a species).

Bembix palmata

Image courtesy Reiner Richter
https://inaturalist.ala.org.au/observations/66902356