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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



The following muscles of segment VIII, here enumerated as mus- 

 cles 10 to 16, are all attached on the spiracular plate of the eighth 

 tergum : 



10. First dorsal muscle. — A very slender muscle in the worker 

 (fig. 43 B), a large muscle in the queen (fig. 44 C), arising dorsally 



VIIT^ 



VIIIV 



Fig. 44. — External genital apparatus, and muscles of the spiracular plate of 

 eighth segment of Apis mellifica, queen. 



A, the sting chamber opened from behind by separation of tergal and sternal 

 plates of seventh segment, showing the complete annulus of eighth segment 

 (VIIIT, yillV), with outer depression (a) of genital chamber at base of 

 ovipositor between folds of eighth venter {VIIIV). 



B, the genital pouches and the oviducts, posterodorsal view, with wall of 

 outer cavity of genital chamber (a) cut away along line bw, and apertures of 

 pouches {c, d) distended. 



C, right spiracular plate of eighth segment and its muscles, mesal view. 



a, shallow external cavity of genital chamber ; b, median pouch of genital 

 chamber ; c, aperture of median pouch ; d, d, apertures of lateral pouches ; e, e, 

 lateral pouches of genital chamber. 



on upper part of inner face of spiracular plate ; inserted ventrally 

 on outer surface of ninth tergal (quadrate) plate anteriorly at base 

 of dorsal apodeme of the latter. 



II. Second dorsal muscle. — Origin on inner face of dorsal lobe of 

 spiracular plate (figs. 43 B, 44 C) ; insertion posteriorly and ventrally 

 on posterior dorsal angle of quadrate plate of ninth tergum (fig. 

 45 A). In the worker this muscle arises just behind 10 (fig. 43 B) ; 

 in the queen (fig. 44 C) it arises external and ventral to origin of 10. 



