Derived from several figures in (1).

On the left, the commonly defined areas of the head are shown.
Clp, clypeus
E, compound eye
Fr, frons
Ge, gena
Lb, labium (with labial palpus)
Lm, labrum
Md, mandible
Mx, maxilla (with maxillary palpus)
Oc, occiput
Poc, postocciput
sge, subgena
Vx, vertex

On the right, "the common external sulci ... (generally called “sutures”)" (Snodgrass 1960) are shown.
cas, circumantennal
cos, circumocular
es, epistomal
ocs, occipital
pos, postoccipital
sgs, subgenal
sos, subocular

These images replace, in part, two hand-drawn figures uploaded in 2005 which were improperly removed and frassed in January 2025.