THE MUSCULAR SYSTEM OF GRYLLUS ASSIMILIS FABR. 

 ( = PENNSYLVANICUS BURM.) 



E. Melville DuPorte, 

 MacDonald College (McGill University), Canada. 



Introduction. 



This paper gives an account of the musculature of Gryllus 

 assimilis Fabr., one of our common field crickets. It includes 

 also a brief description of the internal skeletal structures 

 inasmuch as a knowledge of these is necessary to understand 

 the method of attachment of the muscles. 



In his comprehensive study of the thorax of G. domesticus 

 Voss ('05) describes the musculature of the veracervix, the 

 thorax and the anterior segments of the abdomen. Berlese ('09) 

 figures some of the thoracic muscles of G. campestris. The 

 musculature of these two insects agrees very closely with that 

 of the allied G. assimilis. 



In naming the head muscles, including those of the neck, 

 I have employed terms descriptive of their functions without 

 reference to possible segmental homology. I have followed 

 Voss and Berlese' s system in naming the thoracic and 

 abdominal muscles, and have not described these muscles in 

 detail, owing to their general similarity to the muscles of 

 G. domesticus as described by Voss ('05). The numbers used 

 by Voss are inclosed in square brackets after the description 

 of the muscles; the names which he used for the cervical 

 muscles are also thus inclosed, Crampton's term veracervix 

 being substituted for microthorax. 



I have thought it best to avoid the use of Latin terms. 

 The numbers used have no significance apart from their reference 

 to the figures. 



16 



