The head is extended from behind forwards, so that the crown (epicranium) is large, while the face (clypeus) is small.
The face (clypeus) is (Grooved Whirlibroad, extending on either side gig).
Below this comes the front, and then the face or clypeus, to which a very distinct upper lip (labrum) is usually jointed.
A, Front; B, side; C, back; v, vertex; f, frons; cl, clypeus; lbr, labrum; oc, compound eye; ge, gena; mn, mandible; ca, st, pa, ga, la, cardo, stipes, palp, galea, lacinia of first maxilla; sm, m, pa', pg, submentum, mentum, palp, galea of 2nd maxilla.
Ia, frons; b, clypeus (the pointed labrum beneath it); II, mandible; III, first maxilla; (a, base; b, sheath; c, piercer), III', inner view of sheath; IV, second maxillae forming rostrum (b, mentum; c, ligula).
The labrum and clypeus are developed as a single prolongation of the oral piece, not as a pair of appendages.
Of the head-capsule in the imago, it appears that the clypeus and FIG.
A, anus; Abx 1 Abx 11, appendage of 1st and of 11th abdominal segments; Ans, anal piece=telson or 12th abdominal segment; Ant, antenna; De, deuterencephalon; Md, mandible; Mx1, first maxilla; Mx2, second maxilla or labium; 0, mouth; Obcl, rudimentary labrum and clypeus; Pre, protencephalon; St t, Stu), stigmata i and io; Terg, tergite; Thx1, appendage of first thoracic segment; Tre, tritencephalon; Ul, a thickening at hinder margin of the mouth.
- A, Front of head of Sawfly (Pachynematus); a, labrum; b, clypeus; c, vertex; d, d, antennal cavities.
I., a, frons; b, clypeus; I'., Same from behind.