ELEMENTARY ZOOLOGY 



any 



of the 



The alimen- 



FIG, 47. Piece 



other invertebrates. The muscular system 

 comprises a large number of distinct mus- 

 cles, usually small and short, which are 

 disposed so as to make very effective the 

 various complex motions of antennae, 

 mouth-parts, legs, wings, and egg-laying 

 organs. The muscles appear to be 

 very delicate, being almost colorless 

 when fresh, but they have a high 

 contractile power, 

 tary canal is di- 

 vided into various 

 special re- 

 gions, a s 

 pharynx, cesopha- 

 of gus, crop, fore 

 stomach or gizzard, 



the giant-crane- digesting Stomach, 

 fly. (Photo-micro- . 



graph by Geo. O. and small and large m- 



Mitchell.) testine. From the canal 



just at the point of union of the digesting 

 stomach (ventriculus) and the small in- 

 testine rise the so-called Malpighian 

 tubules, which are excretory organs. 

 They are long slender diverticula of the 

 alimentary canal, and are typically six 



(three pairs) in number. The circula- FlG - 48. The anten- 

 na of a carrion bee- 

 tory system is composed of a tubular tie, with the termi- 



vessel running longitudinally through the 

 body in the median line just under the 

 dorsal wall. It is composed of a series 

 of chambers or segmental parts, which 

 by a rhythmic contraction and expansion 

 propel the blood anteriorly and into a 

 short, narrow, unsegmented anterior portion of the vessel 



nal three segments 

 enlarged and flat- 

 tened, and bearing 

 many ' smelling- 

 pits/' the antenna 

 thus serving as an 

 olfactory organ. 

 (Photo -micrograph 

 by Geo. O.Mitchell.) 



