20 



DIPTERA 



[CH. 



egg-tubes. The female, in addition, has three spermathecae, 

 paired accessory organs, and no true bursa copulatrix. The 

 male has two oval testes with short ducts, communicating with 

 a well-developed penis, surrounded by accessory copulatory 

 appendages. 



Reproduction. 



The great majority of flies lay eggs, which are generally 

 deposited in such a position that the young larva will be in 

 easy reach of its food-supply. A number of families, however, 

 are more or less viviparous, the eggs hatching within the body 

 of the parent and the resulting larvae nourished for varying 

 periods before being liberated. In the majority of such cases 

 the larvae are deposited whilst quite young, but in the Pupipara 

 and Glossina the larvae are nourished within the oviduct of the 

 mother until quite full-grown and when set free at once proceed 

 to pupate. 



Fig. 7. 



Fig. 6. 

 Fig. 6. Acephalous larva of Stomoxys calcitrans (xy). After Newstead. 



cst, compound thoracic stigmen ; ast, posterior stigmen. 

 Fig. 7. Fucephalous larva of Phlebotomus papatasii. After Newstead. 



