GLOSSINA: REPRODUCTIVE ORGANS 141 



no elaborate arrangement of milk glands, such as is found in the true 

 Pupipara, for the nourishment of the growing young. There is a single 

 pair of accessory glands, which open at the upper end of the common 

 oviduct ; these are certainly much larger than those found in the 

 oviparous forms. 



The spermathecae resemble those of Musca, two of them, however, 

 being inserted by a common duct. All three ducts are very much coiled. 



The following account of the female reproductive tract of Glossina is 

 taken from Roubaud. The writers have not had the opportunity of 

 examining Glossina in the fresh state. 



The apparatus consists of two parts, the ovaries and their accessory 

 organs (spermathecae and milk glands), and the unpaired portion, the 



oviduct, uterus, vagina, and the common duct of the 



... . . Glossina 



milk glands. 



The ovaries are of the same type as those of Musca bezzii. There 

 is one ovariole on each side, containing at most four or five follicles, 



and the two sides function alternately, first one and 



-11 Ovaries 



then the other producing a mature egg in the lowest 



follicle. As in bezzii, the upper follicles are so much outgrown by 

 the lowest one that they appear to be attached to its lateral aspect. 

 Each ovarian tube opens by a short canal into the median unpaired 

 oviduct, which in turn opens, after a slight dilatation, into the upper 

 end of the uterus. The walls of the ovarian tube are composed of an 

 external layer of muscle fibre, and an internal fibrous layer adherent to 

 this. 



The uterus is a large distensible sac, the dimensions of which neces- 

 sarily vary according to the state of the development of the larva ; when 



the larva has attained to full growth it occupies almost 



Uterus 

 the entire ventral region of the abdomen. It is held 



in position by a rich tracheal network, best developed on the ventral 

 surface and at the sides, and by various muscles, the arrangement of 

 which has been described by Minchin. The disposition of these is 

 sufficiently indicated in the figure (Plate XXX) ; in addition to those 

 shown there is a large unpaired muscle in the middle ventral line which 

 connects the uterus with the ventral abdominal wall. These muscles 

 support the heavy uterus during gestation and are able to adjust its 

 position in the abdominal cavity. 



The walls of the uterus are composed of an external tunic of muscle 

 fibres, arranged in longitudinal, circular and oblique bands, and a fine 

 chitinous lamina on the internal aspect. The oviduct, which leaves the 



