14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



arise on a median apodeme in the posterior gular region; all these 

 muscles are inserted at the base of the maxilla. There is a small labial 

 muscle, probably the ventral muscle of the lahimn, 21 (figs. 39, 40), 

 that arises at the base of the postmentum adjacent to the posterior 

 tentorial pits ; it is inserted medially and basally on the prementum. 

 In Hydrous there are five pairs of powerful muscles that arise 

 on the anterior tentorial arm and are inserted at the base of the 

 maxilla. There is a muscle present, probably the ventral muscle of 

 the labium, 21, and another that is inserted on the dorsal region of 

 the labium which may be the dorsal muscle of the labium, 20. The 

 dorsal dilator muscles of the cibarium, 6 and 7, the dorsal dilator 

 Wrusclcs of the pharynx, p and ii, the muscle of hypo pharyngeal bar 

 Y, 10, and the compressor muscle group of the cibarium are all similar 

 to those in Sphaeridium though they are much more massive. The 

 ventral muscles of the pharynx are large and complicated in 

 arrangement. 



VII. CUCUJOIDEA 



In this group Scotobatcs calcaratus (Fab.), Tenebrionidae, and 

 Epilachna corrupta Muls., Hippodaniia convergens Guer., Coccinel- 

 lidae, adults were used for study. In Scotohates (figs. 41, 42, 43) 

 the labral, cibarial, pharyngeal, and hypopharyngeal muscles are pres- 

 ent and well developed. Bar Y (fig. 41) is connected with the anterior, 

 distal edge of the anterior tentorial arm by means of a flat, sclerotized 

 band. The ventral muscle of the labium, 21 (figs. 41, 42), may be 

 homologous with that of Periplaneta, but its origin is on the anterior 

 region of the postmentum and not on the tentorium. The dorsal 

 muscle of the labium, 20 (figs. 41, 42), arises in the usual manner, 

 but it is inserted medially on the inner side of the anterior labial wall 

 and might easily be interpreted as the muscle of the hypo pharynx, jp. 



In Epilachna there is only one labial muscle; it corresponds with 

 the ventral muscle of the labium, 21, in Scotobates. The muscles of 

 the labrum, cibarium, and pharynx are essentially the same as those 

 in Scotobates, with a slight variation in arrangement. The muscle of 

 hypopharyngeal bar Y, 10, lies laterad of the ventral muscle of the 

 labrum, j. Tiie dorsal dilator muscles of the pharynx are very 

 powerful. 



In Hippodamia convergens Guer. the musculature is practically the 

 same as in Epilachna. The compressor muscle group of the cibarium, 

 12, is well developed. 



Scotobates calcaratus (Fab.), Tenebrionidae, Hippodamia con- 

 vergens Guer., Coccincllidac, and Synchroa puncta Newn., Syn- 



