HEAD, MOUTH-PARTS, ORTHOPTERA EUPLEXOPTERA 285 



through the latter; that the Locustidae and Acridiidae come 

 next in the order named, and that the Phasmidae appears to be 

 most remote from the Blattidae, although its exact phylogenetic 

 position cannot be determined. The Forficulidae possess evi- 

 dences of orthopteran affinity in their general morphological 

 organization, but differ from the Orthoptera in the character of 

 the maxillae, parapharynx, and labium. 



The structures dealt with in this study are summarized as 

 follows : 



3. The exoskeleton of the head consists of vertex, front, 

 clypeus, labrum (preclypeus and postclypeus) , mandibulariae, 

 occiput, postgenae, and maxillariae. The vertex includes the 

 genae and bears the compound eyes, ocelli, antacoriae, and 

 antennariae. The occipital foramen is bounded by the occiput, 

 postgenae, and maxillariae. 



4. The endoskeleton of the head: 



5. The movable parts of the head : 



