^39 



s'terna. The last ganglion lies just below the 

 junction of the oviducts to form the common ovi- 

 duct. A large nerve passes from it among the 

 virxera of the last few segments. 



The Visceral System. — Small ganglia con- 

 nected with the main ganglionic system occur in 

 connexion with the viscera. The most important 

 of these are two small groups of large nerve cells 

 lying in front of and above the thoracic ganglion, 

 with the middle portion of which they are con- 

 nected by nerves. They lie laterally beneath the 

 oesophageal diverticulum and anterior portion of 

 the mid- gut, and are not far removed from the 

 salivary glands. Another small ganglion occurs 

 above and in front of the proventriculus (Fig. 34). 



The Reproductive System 



The organs of the reproductive system are : — 



1. Ovaries. 



2. Oviducts and common oviduct. 



3. Mucus gland and duct. 



4. Spermathecae and ducts. 



The ovaries occupy a variable position depend- 

 ent upon the state of their development. In the 

 newly-hatched mosquito they are small bodies 

 lying in the fourth and fifth abdominal segments 

 close by the posterior portion of the mid-gut, and 

 attached to the body wall by numerous tracheae. 

 As they enlarge they push the mid-gut, hind-gut, 

 and malpighian tubes towards the ventrum, so 

 that eventually the ovaries occupy nearly the 

 whole of the posterior portion of the abdomen. 

 Each ovary consists of very many follicular tubes, 

 each containing egg follicles in different stages of 



