NO. 7 MUSCULATURE OF COLEOPTERA — DORSEY 2,^ 



XX. PLATYSTOMOIDEA 



Euparius marmoreus (Oliv.), Platystomidae (figs. 117, 118, 119), 

 is the adult form studied in this superfamily. The labral muscles are 

 absent; the cibarial, pharyngeal, and hypopharyngeal muscles are not 

 well developed. The hypopharyngeal bar Y (fig. 118) is modified into 

 a flat plate. There is a heavily sclerotized subpharyngeal rod, IR 

 (fig. 118), present that supports the ventral region of the mouth and 

 also strengthens the posterior lateral labial walls in which region 

 the ends of the rod terminate. The labial muscles are well de- 

 veloped. The dorsal muscle of the labium, 20 (figs. 118, 119), is an 

 unusual muscle in this species ; it arises laterally in the posterior gular 

 area as a thickened, powerful group of muscle fibers that quickly 

 converge to become inserted on the end of a thin tendon in the anterior 

 gular region. The tendon extends anteriorly and is inserted some- 

 what laterally in the dorsal region of the posterior labial area. 



In the larva of this species (figs. 120, 121, 122) the ventral muscle 

 of the labruni, 5 (figs. 120, 121), is present. The muscle of hypo- 

 pharyngeal bar Y, 10 (fig. 10), is massive; the dorsal dilator muscles 

 of the pharynx, p and 11, are absent in this species. The hypopharyn- 

 geal bar Y (fig. 121) is large; it supports the mouth opening later- 

 ally and is continuous with a heavily sclerotized suboral lobe that is 

 joined on each side by a heavily sclerotized bar, IR (fig. 121), that 

 terminates in the integumental wall of the posterior dorsal lateral 

 region of the labium. The ventral muscle of the labium, 21 (figs. 

 121, 122), arises on the tentorium at the base of the tentorial arm; 

 it is inserted medially on the base of the prementum. There is a divi- 

 sion of the muscle of the prementum, 22 (figs. 121, 122), into two 

 parts ; each arises laterally in the anterior region of the submentum 

 and each is inserted laterally at the base of the prementum. 



XXI. CURCULIONOIDEA 



From this superfamily Pantomorus godmani (Crotch), Curculioni- 

 dae, and Dcndroctonous valens Lee, Scolytidae, were selected for 

 study of the adults. 



In Pantomorus (figs. 123, 124, 125) the muscles are reduced in 

 number and those present are poorly developed. The labial muscles 

 are absent and the cibarial muscles, 7 (figs. 123, 124), are repre- 

 sented by a row of weak fibers inserted through the transverse com- 

 pressor muscle group of the cibarium, 12 (figs. 123, 124), and, since 

 they all do insert through 12, are probably divisions of 7. The muscle 

 of hypopharyngeal bar Y, 10 (fig. 123), is also weak and bar Y (fig. 



