CH. Ill] 



THE COCKROACH 



83 



These tubules are intricately entwined among the other 

 abdominal viscera, and extract from the blood in which 

 they are bathed various nitrogenous compounds, uric acid 

 being that most generally known. 



Respiration. The air enters and leaves the body not 

 by the mouth but by the paired openings (stigmata, 

 spiracles) situated upon the sides of the body. By means 



,4;. 13 



....17 



Fig. 18. A Female Cockroach, Periplaneta, with the dorsal exoskeleton 



removed, dissected to show the viscera. Magnified about 2. 

 1. Head. 2. Labrum. 3. Antenna, cut short. 4. Eye. 5. Crop. 



6. Nervous system of crop. 7. Gizzard. 8. Hepatic caeca. 



9. Mid-gut or mesenteron. 10. Malpighian tubules. 11. Colon. 



12. Kectum. 13. Salivary glands. 14. Salivary receptacle. 



15. Brain. 16. Ventral nerve-cord with ganglia. 17. Ovary. 



18. Spermatheca. 19. Oviduct. 20. Genital pouch in which 



the egg-cocoon is found. 21. Colleterial glands. 22. Anal 



62 



