264 



ANIMAL BIOLOGY. 



[Part II. 



4. In the female, (a) the genital opening on the eighth 

 sternum ; (b) the opening of the spermatheca on the ninth 

 sternum. 



5. In the male, (a) the opening of the ejaculatory duct 

 behind the ninth sternum ; (b) the opening of a subsidiary 

 gland on a double hook, which forms part of the external 

 genital armature. 



At these apertures the chitinous exoskeleton is inflected 

 inwards. 



FIG. 81. COCKROACH ALIMENTARY CANAL. 



A. Alimentary canal dissected out. B. Part of gizzard under simple micro- 

 scope. C. One tooth of the same from the side. 



6. c. Buccal cavity, cce. Pyioric cseca. co. Colon, cr. Crop. gi. Gizzard. 

 II. Ileum. Ib. Labrum. li. Lingua, mn. Mandibles, m. t. Malpighian 

 tubules, ces. (Esophagus, p. p. Podical plate, r. Rectum, s. gl. Salivary 

 glands, s. r. Salivary receptacle, ve. Chylific ventricle. 



The Alimentary Canal. J The alimentary canal of the cock- 

 roach (Fig. 81) has three divisions : (1) a stomodceal section 

 anteriorly, lined with a chitinous layer continuous with the 



1 The cockroach is conveniently dissected, under the simple microscope, or 

 with the aid of a watch-maker's lens, in a shallow tin or glass vessel. In the 

 bottom of such a vessel melt some paraffin, and mix in lamp-black. Allow the 

 paraffin to cool and solidify as a firm cake at the bottom of the vessel. With a 

 hot glass rod rnelt a convenient cavity and imbed therein the cockroach. Dis- 

 sect under water or alcohol. 



