NO. I 



INSECT THORAX — SNODGRASS 



53 



ment (H, Psc), its median part being here often expanded posteriorly 

 until it almost meets the apex of the scutellum (Scl). In Tipulidse (D) 

 and Tenthredinidae (I), the prescutum is reduced to a narrow band 

 (Psc) surrounding the convex anterior margin of the scutum, and ex- 

 tending backward on the sides to the bases of the wings. In some cases, 



Aw 



H, "I 



Fig. 24. — Modifications of the wing-bearing terguni. 



A, inesotergum of Japyx, consisting of a simple segmental plate with a large 

 precosta {Pc) separated by an antecostal suture (flc). B, metatergum of 

 Gryllus assi)>iilis, area behind antecostal suture (ac) partially divided into 

 prescutum (Psc), scutum {Set), and scutellum (Scl). C, mesotergum of 

 Mehiiio/^his foiiur-nihruin. D, mesotergum of llolontsia rubic/inosa ; prescutum 

 (Psc) a narrow band terminating on each side in prealar lobe (») ; scutum 

 marked by three pairs of sutures (tar, x, y) ; a, c, j, b, attachments of tergal 

 muscles (fig. 34 D, A, C, J, B). E, mesotergum of Tabanus atratus: prescutum 

 (Psc) fused medially with scutum; parapsidal sutures (par) extended poste- 

 riorly; scutellum divided by secondary groove (z). V, mesotergum of Cynips: 

 prescutum and scutum fused ; parapsidal sutures cut the scutum lengthwise into 

 three parts (r, a, c). G, mesotergum of Pliassiis arycntiferus. H, metatergum 

 of Calosoma scrutator: scutum divided medially by approximation of prescutum 

 and scutellum, and each half divided by suture (w) into anterior and posterior 

 part (Set, Set). I, mesotergum of Ptcronidca ribcsi: prescutum (Psc) very 

 narrow; parapsidal sutures {par) of scutum convergent; scutum cut by lateral 

 sutures {s). J, mesotergum of Apis iiicllifica: prescutum and scutum united; 

 scutum divided by secondary suture (s) into three parts {Set, set, set). 



