NO. 7 



THE INSECT CRANIUM SNODGRASS 



25 



the labrum, if these muscles are present, the precerebral dilators 

 of the pharynx, the hypopharyngeal muscles (hphnicl), and the 



Fig. 8. — Coleoptera. 



A, Dytiscns sp., Dytiscidae, head of larva, showing distribution of fronto- 

 clypeal muscles (see fig. 13 D). B, Trichodesma gibbosa (Say), Anobiidae, 

 head of larva. C, Crioceris asparagi (L.), Crioceridae, head of larva. D, 

 Dyitastes tityus (L.), Scarabaeidae, head of larva. E, Alaus ocidatus (L.), 

 Elateridae, head of larva. F, Chalcophora sp., Buprestidae, head of larva. 

 G, Leptinotarsa decimlineata Say, Chrysomelidae, head of larva. H, same, head 

 of adult. I, Hydrophilus sp., Hydrophilidae, head of larva. 



dilators of the cibarium (dlcb). The last are separated from the others 

 by the frontal ganglion (FrGng) and its cerebral connectives. In 

 some beetle larvae the frontoclypeal region is divided between frons 



