1920] Dit Porte: Muscular System of Gryllus 37 



(d) Tarsal Muscles. 



The Extensor of the Second and Third Tarsal Segments (Fig. 23, 

 ext. tar. 2) lies in the dorsal side of the first tarsal segment. It 

 originates in the proximal end of the segment and is inserted into 

 the dorsal proximal edge of the second segment. When this last 

 is extended it pulls the third segment with it so that the two 

 segments move together. 



The Extensor of the Claws (Fig. 23, ext. ung.) originates from 

 the proximal end of the dorsal side of the third tarsal segment 

 and is inserted into the base of the claws by means of a tendon, 

 which forms a bridge between them on the dorsal side. 



The Flexor of the Claws (Figs. 23 and 27, fl. ung.) originates 

 on the ventral side of the third segment opposite the origin of 

 the extensor. Connected with the base of the claws on the 

 ventral side is a prominent apodeme (Fig. 27, ap. ung.) at the 

 end of which the flexor is inserted by a long narrow tendon. 



IV. MUSCLES OF THE ABDOMEN. 



(Plate VI, Figs. 32-36.) 



A. First Abdominal Segment. 



LONGITUDINAL MUSCLES. 



(a) Sternal. 



73. The First Ventral Muscle (Fig. 32). From near the 

 antero-lateral edge of the first sternite, into the anterior edge 

 of the second sternite. [26]. 



74. The Second Ventral (Fig. 32). From the lateral side 

 of the first sternite into the inner angle of the parasternal 

 plate. [27].. 



(b) Tergal. 



75. The First Dorsal Muscle (Fig. 32), Two straight flat 

 muscles lying in the tergum near the median line. They 

 originate from the posterior edge of the tergite and are inserted 

 into the anterior edge of the second tergite. [28]. 



76. The Second Dorsals (Fig. 32). Origin contiguous to 

 that of 75; inserted into the lateral end of the anterior edge of 

 the second tergite. [29]. 



The longitudinal muscles are retractor muscles of the 

 abdomen. 



