348 Annals Entomological Society of America [Vol. XI, 



is clearly evident. The grasshopper group thus differs from 

 the crickets and katydids, in which the union of the mesothorax 

 and metathorax is much less close, especially in the sternal 

 region. 



■ The Neck Region. 



In front of the prothorax, of which it is a part, is a mem- 

 branous neck region (Plate XXXII, Fig. 1, "vc"), called the 

 eucervix or veracervix, by means of which the head is attached to 

 the prothorax ; and the membranous character of its integument 

 permits a greater freedom of movement to the head. Since 

 this membranous region might offer a more vulnerable point 

 of attack than the more heavily chitinized segments, it is pro- 

 tected by the forward-projecting, anterior margin of the pro- 

 notum, into which the head fits, as in a collar. 



Embedded in the more membranous walls of the neck 

 region are several small plates called jugular sclerites, cervical 

 sclerites, or cervicalia, which serve to strengthen the walls of the 

 neck and to furnish points of articulation for the head. Some 

 of them were also formed as points of attachment for certain 

 muscles, since they offer a firmer support for muscle attach- 

 ment than the more yielding membranous walls of the neck 

 region. These sclerites are homologous with the interseg- 

 mental sclerites occurring between the different thoracic seg- 

 ments in certain lower insects, and therefore are not to be inter- 

 preted as representing the labial segment, or the remains of a 

 rudimentary segment between the head and prothorax (see 

 Crampton, 1917). In the grasshoppers only the lateral and 

 ventral cervical sclerites are preserved. The anteriormost lateral 

 cervical sclerite (Figs. 2 and 1, "Ic") supports the head. The 

 ventral one. Fig. 2, "ps" is homologous with the so-called 

 presternum of lower insects. 



The Pronotum. 



The pronotum is a large saddle-shaped or "sunbonnet- 

 shaped" structure which extends over the greater portion of the 

 dorsal and lateral regions of the prothorax, and projects back- 

 ward over the anterior portion of the segment behind it. The 

 projecting posterior region of the pronotum is called the "hind 

 process of the pronotum'' by systematists (Text figure 2, "x"). 

 The two postero-lateral margins of the pronotum form an angle 



