Head and mouth-apparatus of the larva of  Symmerus  annulatus MEIG.  ( Ditomyiidae ).
1 -- head, dorsal view.  2 -- head, ventral view.
3 -- Upper Lip (labrum), right : dorsal view, left : ventral view.  4 -- Mandible, ventral view.  5 -- Maxilla and Lower Lip (labium), ventral view.  6 -- Hypopharynx.
fr = frontal plate,  lpl = side-plate of head-capsule,  lbr = upper lip (labrum),  lb = lower lip (labium),  st = stipes,  crd = cardo.
(After KRIVOSJEINA, 1969)