38 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO7 



dlob hphmcls 



FrGng- fr.^ 



Hphy Lb 



Fig. 13. — Examples of widely different head structures of various insects 

 having the hypopharynx and labium united, showing the constant relation of 

 the cibarial, hypopharyngeal, and stomodaeal muscles to the frontal ganglion 

 connectives and to the clypeal and frontal areas of the head wall. 



A, Popillia japonica Newm., Coleoptera, adult, lateral view of mouth region : 

 cibarium (C6) entirely preoral, frontal muscles of hypopharynx inserted on oral 

 arms (j) of hypopharyngeal suspensoria (HS). B, Malacosoma americana 

 (F.), Lepidoptera, larva, section of anterior part of head, showing cibarial and 

 stomodaeal muscles ; cibarium postoral, continuous with stomodaeum ; brain in 

 head. C, Tip^da abdominalis (Say), Diptera, larva, sagittal section of invagi- 

 nated head : cibarium preoral ; brain in thorax. D, Dytiscus sp., Coleoptera, 

 larva, dorsal view of cibarium and pharynx, with muscles : cibarium postoral, 

 transversely elongate, its dilator muscles (dlcb) separated from hypopharyngeal 

 and pharyngeal muscles by frontal ganglion connectives. E, Tabanus reinwardtii 

 Wied., Diptera, larva, sagittal section of head: cibarium (CbP) a long sucking 

 tube with its dilator muscles extending along entire dorsal surface of cranium ; 

 stomodaeum and brain in thorax. F, Dynastes tityus (L.), Coleoptera, larva, 

 dorsal view of united hypopharynx and labium, showing frontal muscles of 

 hypopharynx attached on oral arms penetrating the mouth angles. 



