PLATE III. 



Fig. 24:.— Head of a Cricket, Ental Surface of flic Dorsal Wall. 

 This shows: as, the ocular sclerites, which may be the basal segment 

 of the ocular appendage; as, the antennal sclerite, which represents the 

 lateral field of the antennal segment. 



Fig. 25. — Head of the Nymph of Pteroiarcijs. 



(After f'omstock iiud Koctii.j 



In this the antennal sclerites (as) are distinct and closer to the cly- 

 peus than in the more specialized insects, showing that it is possible that 

 they were once closely connected with the clypeus (c) and a part of the 

 same segment. 



Fig. 26. — Lateral Cervical Sclerites of Melu)topliis. 



These are taken to represent the epimeron (em) and episternum (c) 

 of the labial segment. 



There is present a prominent apodeme U'P), and the epimeron con- 

 nects with the episternum of the prothorax, and the episternum (es) 

 with what is considered the epimeron of the maxillary segment. 



Fig. 27. — Head of Sienopclmatus, Ventral Aspect. 



(AI'Ut ('omsloi'k ami Koi-hi.) 



This shows the ventral cervical sclerites in two transverse series, 

 S and S2. These may be regarded as the sternum and sternellum of the 

 labial segment. 



Fig. 28. — Ventral and Laicial Cerrical Sclerites of I'eriplaiiata. 

 This shows the two single cervical sclerites — the sternum (s) and the 

 sternellum (si'} of the labial segment; also the lateral cervical sclerites 

 — the episternum (es) and the epimeron (em) of the labial segment. 



Fig. 29.— \'cntral Cervical Sclerites of Grijlliis. 



In Grylhis, as in Stcnopelmatus the ventral cervical sclerites are ar- 

 ranged in two transverse series. 



Fig. .30. — Hi/popliaryiu- of Melariopliis. 



This shows the lingua (/) and the superlinguae (si), the sole remain- 

 ing traces of the superlingual segment. These are small sclerites, prob- 

 ably representing the appendages of that segment. 



This also shows the pharyngeal sclerites (;as), the sternal elements of 

 the mandibular segment. 



Fig. si.— Head of a Cricket, Caudal Aspect. 

 Pg. — Postgenae. 

 Es. — Episternum. 

 Em. — Epimeron. 

 M. ap. — Mandibular apodeme. 

 Bt. — Body of tentorium. 

 Ex. h. — Extensors of the head. 

 D. ap. — Dorsal apodeme. 



This is to show the parts that are considered as belonging to the 

 mandibular segment. 



