46 



REPRODUCTIVE ORGANS OF A LOCUST. 



1. Two testes, each testis consisting I. 



of many testicular follicles. 



2. Two vasa defereiitia. 2. 



3. Several seminal vesicles, each 3. 



an appendage of a vas def- 

 erens. 



4. Two accessory glands, each an 4. 



appendage of a vas def- 

 erens. 



5. An ejaculatory duct, the united 5. 



vasa deferentia. 



6. A penis. 



Two ovaries, each ovary consist 

 ing of many egg-tubes. 



Two oviducts. 



Two egg-calyces, each calyx an 

 enlarged portion of an ovi- 

 duct. 



Two colleterial glands, each a 

 cephalic prolongation of an 

 oviduct. 



A vagina, the united oviducts. 



6. An ovipositor. 



7. A bursa copiilatrix and a jr/^r- 

 , 7natheca with a ^/wf/ connect- 

 ing them. 



The respiratory system. —Return to the study of 

 Corydalis. Make a diagram showing the arrangement of 

 the larger tracheae. 



The walls of the tracheae are 

 composed of three layers, which 

 correspond to the layers of the 

 body-wall ; in fact the tracheae 

 are invaginations of the body- 

 wall. The continuity of the 

 membranes of the tracheae and 

 body-wall is shown diagrammat- 

 ically in Figure i. It should 

 be observed that it is the inner 

 layer of the wall of the tracheae 

 that corresponds with the outer 

 layer of the wall of the body. 



This inner layer of the wall of 

 the trachea, the intima, like the 

 cuticle, is chitinous, and is shed 

 from the trachece with the cuticle when the insect molts. 

 This layer of the trachea is furnished with thickenings, which 



Fig. I. — Section of trachea and 

 body-wall, c, cuticle ; hy, hypo- 

 dermis ; sp, spiral thickening of 

 the intima. The third layer is 

 a delicate membrane bounding 

 the ental ends^of the hypoder- 

 mal cells ; this is the basement 

 membrane. 



