MOUTH PARTS OF THE NYMPH. 



Epipharynx. 



The epipharyngeal muscles (PI. Ill, fig. 35, epl, ep2) are two cone-shaped 

 muscles attached to the inner surface of the labrum and epipharynx near the 

 median line. 



II. Mandible. 



Flexor. The flexor of the mandible (PI. Ill, fig. 34, Fl ; PI. H, fig. 26, Fl) 

 is a large three-parted muscle attached to the anterior part of the body of the 

 tentorium (Tn), and inserted at the outer wall of the body of the mandible. 



Adductor. (Adducteur des mandibules, Str.-D. ; flexor mandibulae, Burm. ; 

 musculus flexor mandibulae, Bauer). The adductor of the mandible is a strong 

 pyramidal shaped muscle (PI. Ill, fig. 34, ad), its attachment filling the anterior 

 part of the head capsule as far forward as the eye and upper part of the brain. 

 It is inserted by a strong sheath-shaped tendon at the upper, inner angle of the 

 dorsal surface of the mandible (PI. II, fig. 26, ad). 



Abductor. (Abducteur de la mandibule, Str.-D.; extensor mandibulae, 

 Burm.; musculus extensor mandibulae, Bauer). The abductor of the mandible 

 (PI. Ill, fig. 34, Abd; PI. II, fig. 26, Abd) is a slender muscle inserted at the 

 lower outer-angle of the ventral surface by a short tendon, and attached to the 

 postgena at a level with the top of the eye. 



The mandible is attached on its dorsal surface to the postgena by a large 

 heavily chitinized articulation (PL II, fig. 26, 25 ga.) and ventrally at its lower 

 inner angle by a much smaller ginglymous joint (fig. 25, 26 ga. ; fig. 27). With 

 these two articulations as pivots the mandible rocks toward the median line in a 

 dorso-ventral plane. 



III. Hypopharynx. 



Elevator. The elevator of the hypopharynx (PI. Ill, fig. 36, El) is inserted 

 at the ventral basal angle of the median lobe, and attached to the midlabial 

 apodeme. 



Retractor. The retractor of the hypopharynx (PI. Ill, fig. 36, R) is a long 

 slender muscle inserted on the dorsal surface at the point of fusion of the lateral 

 and median lobe. It is attached to the base of the central plate of the tentorium 

 at the side of the labial retractor. 



Depressor. The depressor of the hypopharynx (PI. Ill, fig. 36, d) is a 

 single muscle attached to the midapical region of the median lobe and inserted 

 in the central apodeme (ap.). With the retractor this muscle aids in opening the 

 pharynx. 



Compressor. The compressor of the hypopharynx (PI. Ill, fig. 36, co) is 

 a mid-lateral muscle attached to the junction of the labium and hypopharynx, and 

 inserted at the central apodeme (ap.). With the elevator it aids in blocking the 

 pharyngeal opening. 



