INSECT ABDOMEN SNODGRASS 



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M. dorsalis hit emus lateralis (dil). — A narrower band of fibers 

 on lateral area of dorsum, attached anteriorly on tergum IV just 

 behind marginal apodeme (a), extending posteriorly and ventrally 

 to antecosta of tergum V. 



M. dorsalis cxternus (de). — A short protractor muscle. Origin 

 on posterior margin of tergum IV ; insertion anteriorly on marginal 

 tergal apodeme of segment V. The corresponding muscles of seg- 

 ments // and /// are more oblique or almost transverse in position. 



The innervation of 



the protractors, which according to INIorison 

 IV V 



vim vil 



Fig. 39.- — Muscles in right half of first five abdominal segments of Apis mcl- 

 lifica, worker, with muscles of dorsal and ventral diaphragms omitted. 



a, anterior tergal apodeme ; b, anterior sternal apodeme ; c, lateral sternal 

 apodeme ; ds, dorsal muscles of metathorax attached on propodeum ; de, external 

 dorsal muscles ; dil, lateral internal dorsal muscles ; dim, median internal dorsal 

 muscles ; dls, dilator muscle of spiracle ; e, dorsal wall of pouch of petiole ; //, 

 2I, j/, first, second, and third lateral muscles ; ve, external ventral muscle ; vil, 

 lateral internal ventral muscles ; vim, median internal ventral muscles. 



is from the ganglion of the more anterior segment in each case, 

 shows that these muscles belong to the segments giving attachment 

 to their posterior (morphologically anterior) ends. 



M. venfralis internus medialis {vim). — A strong oblique muscle 

 extending from antecosta of sternum IV posteriorly and medially to 

 antecosta of sternum V. 



M. ventralis internus lateralis (vil). — A narrow lateral oblique 

 muscle from anterior part of sternum IV, close to or beneath origin 

 of vim, to anterior apodeme (b) of sternum V. 



M. ventralis externns {ve). — A short sternal protractor arising 

 on posterior part of sternum IV ; insertion anteriorly on anterior 

 apodeme of sternum V. 

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