NO. 7 MUSCULATURE OF COLEOPTERA — DORSEY 3I 



(adult) (fig, 23, PTN), but the hypopharyngeal muscle, ig, does 

 not originate on it in this species. 



The prementum is divided into two sclerites in the coleopterous 

 larvae of : Silpha americana L., Silphidae ; Byrrhns sp., Byrrhidae ; 

 Nosodendron calif ornicunv Horn., Nosodendridae ; Hylecoetus lugu- 

 bris Say, Lymexylidae; and Leptinotarsa decimlineata (Say), Chrys- 

 omelidae. The muscle of the prementum, 22, occurs in all of these 

 larvae; and the muscle of prementum i, 22 A (fig, 48), was found 

 only in the larvae of Byrrhus sp., Byrrhidae. 



In Sphaeridium scarabaeoides L., Hydrophilidae (adult), the ven- 

 tral muscle of the labrum, j (figs. 35, 37), arises on the distal end 

 of the anterior tentorial arm instead of on the dorsal head wall as 

 is the usual manner. In 5^. bipustulatum Fabr. (larva) muscle J7 

 (fig. 39) arises on the posterior lateral margin of the subpharyngeal 

 supporting area and is inserted on the base of the cardo ; this muscle 

 was not observed in other insects. 



It was found that in Scotobates calcaratus (Fab.), Tenebrionidae 

 (adult), the anterior tentorial arm, AT (fig. 41), is connected with 

 hypopharyngeal bar Y by means of a thin, flat, sclerotized band. 



A heavily sclerotized intralabial brace or rod {IR) that terminates 

 laterally in the integument of the posterior lateral labial region is to 

 be found in Coleoptera in: Cyllene robiniae (Forst.), Cerambycidae 

 (adult) (fig, 99, IR) ; Macrobasis immaculata (Say), Meloidae 

 (adult) (fig. 88, IR) ; Leptinotarsa decimlineata (Say), Chryso- 

 melidae (adult) (fig. 112, IR); Scotobates calcaratus (Fabr.), 

 Tenebrionidae (larva) (fig, 46, IR) ; Mordella quadripunctata (Say), 

 Mordellidae (larva) (fig. 97, IR) ; Pantomorus leucoloma Boh., 

 Curculionidae (larva) (fig. 127, IR) ; Hylecoetus lugubris Say, 

 Lymexylidae (larva) (fig. 132, IR). 



In Nosodendron calif ornicum Horn, Nosodendridae (adults and 

 larvae), the hypopharyngeal bar Y (figs, 52, 54) is greatly modified 

 and enlarged (more so in the adult) and is continuous with the 

 tentorial structure. In the adult form the mentum covers the pre- 

 mentum (figs, 50, 52), 



In Chauliognathus pennsylvanicus Deg., Cantharidae (adults and 

 larvae), the tentorial structure (figs. 62, 67, TN) is greatly modi- 

 field (more so in the adult) ; a sclerotized resilient bar is present in 

 the integument of the posterior lateral margin of the labium. 



Only in Neotrichophorus carolinensis (Schfr,), Elateridae (adult), 

 of the Coleoptera studied, were both the dorsal (anterior) and ven- 

 tral (posterior) labral muscles, 4 and j (figs. 68, 70), present. In 



