338 



Annals Entomological Society of America [Vol. X, 



Ip 3 



Head of the Neuropteron Hetnerohius. 



Head of the Mecopteron Panorpodes. 



Head of the Dipteron Erioptera armata, O. S. 



Head of the Neuropteron Nemoptera. 



Head of the Mecopteron Bittacus. 



Head of the Dipteron Asyndidum montanum Roeder. 



In all cases, excepting figures 12 and 13, the head is drawn in frontal view- 

 In some figures only basal segments of antennae are drawn. The areas of cross- 

 hatching denote the compound eyes. 



ABBREVIATIONS. 



a — Antenna, or basal segments of 



antenna. 

 ac- — Anteclypeus. 

 c— Clypeus, or clypeal region, 

 d— Mandible. 

 e — Epicranial suture, 

 f — Frontal region. 

 1^ — Labrum, or labral region. 

 Ip — Labial palpus, or terminal portion 



of labium. 



m — Maxilla, 

 mp — Maxillary palpus, 

 o — Occipital region, 

 oc — Ocelli, 

 p — Genal process. 

 t — Tentorial or frontal pits. 

 X — Plical process, or point of attach- 

 ment of cervical fold, 

 y — Line of attachment of cervical fold 

 or plica. 



