Note the small lateral yellow streak on the mesoscutum, just above the tegula (star). The scape (arrow) is black above, yellow below.

The clypeus in this female is wholly yellow, without the black basal mark seen in some other individuals of the same species.

Bembix furcata

A full frontal view is necessary to assess the level of the vertex summit (star) with respect to the eye tops. Here the vertex is well below eye level.

Species vary in the width of the frons (double-headed arrow) relative to the eye height. In this female the frons is broad, the inner eye margins nearly parallel.

Differences in mandible shape between species are subtle, but do provide useful information. Here the mandible has a strong cutting edge (dotted arrow), described by Evans & Matthews as “an oblique cutting edge between the apex and the tooth on the inner margin.”

The number of antennal segments differs between the sexes. Females have just 10 flagellar segments, while males have 11.

Bembix furcata

Of particular importance is the structure and colour of the front basitarsus (arrow), including the number of ‘pecten’ spines. In all Bembix species, tarsal segments 2-4 bear two pecten spines each but the number on the front basitarsus varies from 6 to 42.
Here there are 6 pecten spines on the front basitarsus, which is quite slender. Also of note is the darkened, slightly lobed outer edge.

The spur on the inner apex of the front tibia (green star) is distinctive in some species. Here it is unmodified, ‘simple’.
From this angle, the midline of the clypeus is visibly elevated (red star). The shape of the clypeus is a useful feature for distinguishing between species, although it can be difficult to discern in field photos.

Bembix furcata

While colour patterning typically shows at least some variation within a species, it still provides a useful piece to the ID puzzle.

Two of the thoracic regions of note are the pronotum and the mesopleura. Note that in Bembix, the pronotum is much lower than the mesoscutum. It is often largely concealed in dorsal view, so lateral shots are helpful.

Note too the large pronotal lobe (star), which is extensively yellow in this species.

This angle also demonstrates why the labrum (arrow) can be difficult to see – it is often tucked away under the head.

When digging, females will usually have the mandibles open and forward of the labrum, making their colour easy to determine. In this female they meet the description of ‘yellow’, as the dark apex is universal in Bembix and so is not mentioned in the summary table of species descriptions.

Bembix furcata