NORTH AMERICAN COLEOPTERA. 87 



the gullet, ineinhraneous in structure. Dissecting out this portion 

 and magnifying more highly, we bring into view a narrow, slit-like 

 opening to the gullet or pharynx, guarded in front by a pair of 

 toothed processes, and laterally by a pair of membraneous flaps, the 

 function of which is evidently to protect the mouth opening, and 

 probably also to move into it in due order the food prepared by the 

 preceding structures. Removing the toothed structures for still 

 greater magnification, we get quite a formidable aj)pearance shown 

 at fig. 7, PI. 111. The teeth are but little chitinized, and I cannot 

 see that they are mobile. What function they have is still obscure 

 to me. 



EXPLANATION OF PLAIE II. 



( Copris Carolina) 



Fig. 1. Mandibles and epipliaryiix from below. 



" 2. Mandibles and epipharynx from side and above. 



" 3. Epipbarynx from below. 



" 4. Mandible— the sclerites named and homologized. 



" 5. Maxilla— the sclerites named. 



" 6. Molars or grinders, opposing fares. 



" 7. Mouth opening with protective membraneous flaps. 



" 8. Labial palpi from iunerside. 



EXPLANATION OF PLATE III. 



( Copris Carolina) 



Fig. 1. Head from below, labial structures only. 



" 2. Labial structures from iunerside. 



" ."}. Labial structures from side. 



" 4. Chitinous framework of labial structures. 



" 5. Section through the labium. 



" 6. Ligula and paraglossiw. 



" 7. Toothed processes shielding mouth opening 



TK.\NS. AM. ENT. SOC. XIX APRIL, 1892. 



