72 



The Form of Insects 



the tubes unite into a single duct. Generally the 

 length of the tubes varies inversely as their number; 

 in some insects they are excessively long, and coiled 

 around the food-canal (2, 33, 40, 46). 



Reproductive Organs. — Having now considered 



Fig. 49. —Ovaries of Female Cockroach, with oviducts Od. and colleterial 

 glands CG. Magnified 14 times. From Miall & Denny. 



the various organs whose functions contribute towards 

 the individual life of the insect, we turn to those 

 which are concerned with the production of young, 

 which serve to perpetuate the life of the race. In 

 the cockroach, as in most insects and in most other 



