1917] Veracervix or Neck Region In Insects 189 



the posterior one, "ps/' is still large, and is connected with the 

 sternal plate "^/" behind it, as is the case with the ventral 

 mesothoracic intersegmental plate "^5" of intersegmental 

 region III, in Fig. 1. It is thus a very simple matter to homol- 

 ogize the ventral prothoracic intersegmental plates " ps" 

 (i. e. the neck plates) of intersegmental region I of Figs. 3 and 1, 

 with the ventral mesothoracic and metathoracic interseg- 

 mental plates ''ps'' of intersegmental regions III and V, 

 (Fig. 1). In the same way, the lateral prothoracic interseg- 

 mental plates "ip'' of region I are homologous with the lateral 

 mesothoracic and metathoracic intersegmental plates "f^" 

 of regions III and V (Fig. 1). Similarly, the tergal prothoracic 

 intersegmental plates "7'/" of intersegmental region I (Fig. 4) 

 are homologous with the tergal mesothoracic (and also with 

 the tergal metathoracic) intersegmental plates "z7" of inter- 

 segmental region III, etc. (Fig. 4). 



It is thus a very simple matter even for the veriest tyro in 

 the study of comparative anatomy to homologize interseg- 

 mental region I (i. e. the neck region) with intersegmental 

 regions III and V (Figs. 1, 3 and 4), and if comparative morpho- 

 logy has any meaning at all, intersegmental regions III and V 



ABBREVIATIONS. 



Int — Intersegmental regions between labial segment and prothorax; between 

 prothorax and mesothorax; and between mesothorax and metathorax. 



ip — Interpleurites, or lateral intersegmental plates. 



it — Intertergites, or dorsal intersegmental plates. 



L — Labium. 



Is — Laterosternite, or lateral plate of sternum. 



Mes — Mesothorax. 



Met — Metathorax. 



Mx— Maxillae. 



n — Notum or tergum. 



Pro — Prothorax. 



pi — Pleural plate (Eupleuron) . 



po — Post-coxal plate (Postcoxale). 



ps — Interstemites or sternal intersegmental plates, the posterior one being the 

 presternite. 



st — Sternum. 



t — Eutrochantin . 



Tf— Trophifer, or sclerite to which labium and maxillae are articulated. 



I — Veracervix, or prointersegment, the first intersegmental region which is largely 

 prothoracic. 



II — Remainder of prothorax. 



Ill — Mesointersegment, or second intersegmental region which is largely meso- 

 thoracic. 



IV — Remainder of mesothorax. 



V — Metaintersegment. 



VI — Remainder of metathorax. 



