228 Aiuiah Entomological Society of America [Vol. XI, 



DESCRIPTION OF A GENERALIZED HOMOPTEROUS THORAX. 



Suborder Homoptera, Family Cicadidse; Cicada tibicen, Crypto- 

 tympana epithesia. Figures 1, 2, 3, 4, 5. 



These insects have been selected for detailed description as 

 being probably rather primitive Hemiptera. They have the 

 additional advantage of being comparatively large and therefore 

 easy to study. 



Between the thorax and the head are three pairs of small, 

 free plates, the cervical intersegmentalia (Figures 2 and 3, is). 

 These probably belong, partly to the head, partly to the pro- 

 thorax. They may all be included under the term veracervix 

 of Crampton, 1914B. 



Prothorax. Figure 3. 



This segment, as compared with the prothorax of the more 

 specialized forms, is small, overlapping only a slight portion of 

 the mesothorax. 



Notum. Figure 3. The notum or tergum occupies the 

 larger part of this segment, extending downward laterally for a 

 considerable distance. There is a narrow pretergite (prt) 

 marked off on the anterior margin and connected with the 

 pleuron by a lateral extension which is homologous with the 

 prealare (pra) in the wing bearing segments. There are no dis- 

 tinct sutures in the prpnotum, but there are several grooves or 

 furrows which mark off a triangular prescutum (psc), a scutum 

 (sc), which is narrow mesally and widens as it approaches the 

 pleuron, and a scutellum (si) , a rectangular band along the rear 

 margin of the segment. The postscutellum is probably not 

 represented in this segment. 



Pleuron. Figures 2 and 3. The pleuron of the prothorax is 

 much reduced and is closely joined to the notum. It is divided 

 into an anterior portion, the episternum (es), and a posterior 

 portion, the epimeron (em), by a short pleural suture (p). The 

 episternum is small and is connected with the sternum by a 

 narrow precoxal bridge, the precoxale (pcx), from which it is 

 not distinctly separated. The epimeron is larger, overlapping 

 the mesopleuron to some extent. It likewise is joined to the 

 sternum, by a postcoxal bridge, the postcoxale (poc). The 

 trochantin (tn) is rather broad, and when in position partly 

 overlaps the base of the coxa (ex) . 



