30 Annals Entomological Society of America [Vol. XIII, 



DORSOVENTRAL MUSCLES. 



(a) Tergo-stemal. 



37, The Mesothoracic Intersegmental Muscle (Fig. 20). 

 Homologue of 21. [73]. 



45. The Seventh Dorsoventral Muscle of the Mesothorax 

 (Fig. 21 B). Origin, precoxale; insertion anterior notal wing 

 process. Present only in the male and long winged female. 

 Elevator of the tegmen. [78]. 



(b) Noto-coxal. 



38, 38a. The First and Sixth Dorsoventrals (Fig. 20). Origin, 

 by two heads from the lateral side of the anterior border of the 

 mesoscutum; insertion by a common tendon into the anterior 

 border of the coxa. The inner belly (38) is broad and stout 

 with parallel fibres, the outer (38a) is slender and conical. The 

 tendon is broad at its base, narrowing into a long linear process. 

 The insertion of 38 is at the broad base of the tendon, that 

 of 38a at the apex of the narrow process (cf. the homologous 

 muscle 59, 59a, Fig. 31). Because of their insertion by a 

 common tendon I have described this muscle and the two 

 following as single muscles. Extensor of the coxa; indirect 

 elevator of the tegmen. [74, 77]. 



39, 39a. The Third and Foiirth Dorsoventrals (Fig. 20). 

 The inner head (39) originates in the scutum, not very far from 

 the median line, the outer (39a) near the postero-lateral edge 

 of the scutum above the posterior notal wing process. The 

 tendon, inserted into the posterior side of the coxa, is bilobed, 

 one lobe being broad and short and the other narrow spatulate. 

 39, a broad, parallel-fibred belly, is attached to the broader 

 lobe, while 39a, a narrow conical belly, is attached to the 

 elongated lobe (cf. 60, 60a, Fig. 30). Voss describes the 

 homologous metathoracic muscles, but states that these muscles 

 are absent in the mesothorax of Gryllus domesticus. On the 

 other hand, I have been unable to find his second dorsoventral 

 muscle either in the mesothorax or metathorax of G. assimilis. 

 Flexor of the coxa. 



(c) Noto-trochanteric. 



40, (40a). The Fifth Dorsoventral and the Third Lateral 

 (Fig. 20). 40 arises in the mesoscutum just laterad of the 

 origin of 39; 40a is a pleuro-pedal muscle originating in the 



