24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



JO (figs. 99, 100), is especially massive. The dorsal wall of the 

 cibarium is decidedly dome-shaped and appears to be able to accom- 

 modate the suboral lobe, SL (fig. 99). The dorsal muscle of the 

 labiuin, 20 (figs. 99, loi), is inserted laterally on the prementum 

 near the dorsal surface. In the posterior lateral region of the sub- 

 pharyngeal area the integument of one side is joined with that of the 

 opposite by a sclerotized intralabial rod, IR (fig. 99). The anterior 

 tentorial arm (fig. 99, AT) is broad but thin. The suboral lobe 

 (.9L) is probably the hypopharynx; a muscle interpreted as the 

 muscle of the hypopharynx, 19 (figs. 99, loi), is inserted medially 

 at its base. 



In Prionus the compressor muscle of the labrum, i, is absent; the 

 muscle of hypo pharyngeal bar Y, 10, is branched. The labral, cibarial, 

 pharyngeal, and hypopharyngeal muscles are similar to those in 

 Cyllene. The labial muscles are similar also, except that the muscle 

 of the prementum, 22, is absent and the ventral muscle of the labium, 

 21, is present. 



In the larval Cyllene robiniae (Forst.), Cerambycinae (figs. 102, 

 103, 104), the muscles are powerful and in the dorsal head region 

 are usually multibranched or subdivided. The labral muscles are 

 absent; the dorsal dilator muscles of the cibarium, 5, 6, and 7 (figs. 

 102, 104), occur in groups and the muscle of hypopharyngeal bar Y, 

 10 and loA (fig. 104), consists of two main branches each of which 

 is subdivided into several units. The compressor muscle group of the 

 cibarium, 12 (figs. 102, 104), is strong; immediately beneath this 

 group the dorsal wall of the posterior region of the cibarium and the 

 anterior pharyngeal region invaginates to form a pouch which, when 

 viewed laterally, is somewhat obovate. This pouch or lobe extends 

 down into the region of the mouth opening. There is a median muscle, 

 40, beneath the compressor muscle group of the cibarium, 12 (figs. 

 102, 104), that arises medially in the posterior region of the pouch 

 and is inserted centrally in the anterior region of the same. The 

 dorsal dilator muscle of the pharynx, 11 (fig. 104), is inserted on 

 the posterior dorsal region of the pouch and the dorsal dilator muscle 

 of the cibarium, y, in the anterior dorsal region. By the combined 

 action of muscles y, 11, 12, and 40 (fig. 104) it would seem that the 

 lobe formed by the ventral wall of the pouch could pull food into 

 the mouth from the shelf like hypopharynx, HY, that lies immedi- 

 ately anterior to it. In the ventral head region the muscle of the 

 hypopharynx, 19, the dorsal and ventral labial muscles, 20 and 21, 

 the ventral and lateral dilator muscles of the pharynx, j?o and 5/ 



