638 



LABORATORY HINTS 



(9) Bothriocephalus. — The only egg outside the trematode eggs 

 with a lid. Oval, cellular contents, but little stained, other- 

 wise much as trematode eggs. Later it becomes encysted, and 

 ciliated for swimming about in water. 



THE DISSECTION OF MOSQUITOES. 



To kill the mosquito, if alive, put it in a test-tube and tap the tube 

 on your arm. 



Remove legs, mount and dry, fixing cover slip with gummed paper 

 having a window in it. Study well the complete structure. 



buccal cavity 



pharynx 



dorsal reservoirs 



oesoph. valve 

 and caeca 



midgut 

 begins 



stomach . 

 malpiqhisn tube - 



midgut ends - - 

 ileum - - 



colon 

 rectum 



Internal anatomy of the mosquito 



