Head and mouth-apparatus of the larva of  Pachyneura  sp.  ( Pachyneuridae ).
1 -- Head, dorsal view.  2 -- Head, ventral view.  3 -- Mandible.  4 -- Maxilla, ventral view.
t = tentorium,  lbr = upper lip (labrum),  fr = frons (frontal plate),  lpl = side-plates of head,  md = mandible,  lb = lower lip (labium),  mx = maxilla,  p.mx = maxillary palp,  lac = lacinia,  st = stipes,  crd = cardo.
(After KRIVOSJEINA, 1969)