T TE STRUCTURE OF MUSCLES 



217 



the sarcolemma represents the cell-membrane. It forms a resistant 

 and extremely elastic tube. The longitudinal (Fig. 236, E) and 

 radiating filaments or reticulum (spongioplasm of Gehuchten) lie in 

 a nutritive filling substance (the hyaloplasm of Gehuchten). The 

 radiating filaments are formed of an exceedingly elastic substance, 

 and serve to sustain the longitudinal filaments, to transmit the ner- 

 vous stimulus to them, and to bring them back into position after 

 contraction. Janet's account agrees on the whole with that of 

 Gehuchten. 



The muscles of flight are said to be penetrated by fine tracheal 

 branches, probably to supply a greater amount of oxygen, as the 



'Sarc 



I'M ..1 ^r-. 



til 



A&^.feisU 



FIG. 236. Preparations from the adductor muscle of the mandible of Vespa crabro, worker, 

 fixed by heat and alcohol several hours after leaving its cell. A to E x 425 ; F x 212 : A, terminal 

 cupule 'of the tendon of a fibre. , C, union of the fibres with their tendon. D, branch of the 

 tendon of a muscle sending out tendons of some of the fibres ; this branch is accompanied with 

 numerous nervous ramifications (N). E, fragment of a nerve which furnishes the ramifications of 

 Fig. D. F, fragment of the tendon of the adductor muscle of the mandible ; at the left are seen the 

 terminal cupules of the fibres (td, C) ; on the right, on the body of the tendons, some sessile cupules, 

 each of which forms the attachment of a fibre ; td, b, tendons of the fibres. After .Janet. 



most energetic movements of the insect are made in moving the 

 wings during flight ; while the other muscles of the body are only 

 surrounded by the air-tubes. (Sharp.) 



Without entering into tedious details, the reader is referred to 

 figures or references to the more important systems of muscles, such 

 as those of the legs and other appendages, of the wings, of respira- 

 tion, etc., to the sections treating of tho^e organs or functions ; also 

 to Figs. 16, 17, 18, 22, 48, 74, 81, 83, 84, 115, 116, 172, 173, 174, etc. 



Muscular power of insects. The most detailed and careful experi- 

 ments are those of Plateau. -His experiments prove that even the 



