1920] Dii Porte: Muscular System of Gryllus 21 



tentorium. The First Adductor (Figs. 13 and 14, ad. mx.) is 

 inserted into the first segment of the cardo at its junction with 

 the second segment near the insertion of the abductor. The 

 Second Adductor (Figs. 12 and 14, ad. 2 mx.) is also inserted into 

 the cardo but at the outer angle of the second segment near 

 the suture between the cardo and the stipes. 



The Flexor of the Maxilla (Figs. 13, 14 and 16, fl.mx.) is a 

 strong compound muscle which also originates from the lower 

 face of the central tentorial plate. It is inserted into a flat 

 elongated apodemal surface (Fig. 15, ap.st.) along the inner 

 edge of the outer wall of the stipes. This muscle and 

 the two adductors working together are capable of exerting 

 considerable force in the closing of the maxillae. 



The Flexor of the Lacinia (Fig. 14, fl.lac.) lies wholly within 

 the stipes. It originates by a broad head near the outer angle 

 of the base of the stipes, runs diagonally across the stipes and 

 is inserted by a short flat tendon into the inner angle of the 

 base of the lacinia. 



The Flexor of the Galea (Fig. 15, fl.g.) is a smaller muscle 

 having its origin in the outer integument of the stipes opposite 

 the palpus and its insertion in the inner angle of the base of the 

 galea. 



Within the stipes there are two muscles which move the 

 palpus. They both originate in the outer integument near the 

 apodeme into which the flexor of the stipes is inserted. The 

 proximal muscle is the Extensor of the Palpus (Fig. 15, ext.p.) 

 and is inserted in the lateral edge of the base of the palpus. 

 The second muscle, inserted at the opposite side of the base of 

 the palpus is the Flexor of the Palpus (Fig. 15, fl.p.). Within 

 each of the first three segments of the palpus there are an 

 extensor and a flexor of the palpal segment. The extensor 

 (Fig. 15, ext.p.s.) arises at the outer side of the base of the 

 segment and the flexor (fl.p.s.) at the inner side. They are 

 inserted respectively into the outer and inner sides of the base 

 of the next distal segment. 



The Labium. The Retractor of the Labium (Figs. 16 and 

 17, r.lb.) is a long flat muscle with its plane at right angles to 

 that of the labium. It originates in the base of the central 

 plate of the tentorium near the inner angle of the postgena, 

 and is inserted into the side of the ligula near the base of the 

 paraglossa. 



