134 MEDICAL ENTOMOLOGY 



form a small receptacle, from which a short common ejaculatory duct 

 passes to the genital opening. On each side there is a globular accessory 

 gland closely pressed against the seminal receptacle. In Tabanus (fig. 1) 

 the testes are similar but a little longer, and have much shorter vasa 

 deferentia, which open into a seminal receptacle of considerable size ; the 

 receptacle is pear-shaped, and receives the vasae at its broad anterior end ; 

 it opens below by an ejaculatory duct into the chitinous penis. It 

 has much muscular tissue in its wall, and presumably plays an active 

 part in expelling the seminal fluid in copulation. 



In Phlebotomiis, the parts of which have been described by Newstead 

 and Grassi, the testes are small oval organs of variable outline, which lead 



by short ducts to a pear-shaped seminal vesicle, which 

 Phlebotomus . J v 



in turn is produced into a short ejaculatory duct. This 

 leads to an interesting apparatus termed by Grassi the ' pompetta '; 

 this consists of a hollow cylindrical chamber containing a piston-like 

 rod, which is provided with muscles by means of which it can be moved up 

 and down ; as the opening of the ejaculatory duct is near the lower end 

 of the chamber, the action of the rod will be, according to Grassi, to 

 regulate the exit of the seminal fluid after the manner of a pump. 



In Mnsca and its allies (fig. 4) the testes are recognized at once by 



their brown colour. They are small pyriform bodies, leading by a 



Musca short and narrow vas deferens to a stouter common 



duct, which may be regarded as the vesicula seminalis. 



Its lower end is contracted to form a short ejaculatory duct. There are 



no accessory glands. 



In Glossina the reproductive organs of the male are different to those 

 of the rest of the Muscidae, and resemble rather the type found in the 

 Glossina Pupipara. The testes are simple tubes of a brownish 



colour and are twisted on themselves in many coils. The 

 testicular tube is continued downwards to become continuous with a vas 

 deferens of slightly greater calibre. These unite in the middle line to 

 form a common ejaculatory duct. There is a pair of accessory glands, 

 twisted on themselves like the testes, but distinguished from them by 

 their white colour and by the fact that they do not terminate in a fine 

 point as do the latter. These open at the point of fusion of the vasae to 

 form the ejaculatory duct. 



In Hippobosca (fig. 4) the testes are simple tubes of very great length, 



and are twisted on themselves to form a compact mass like a ball of string. 



Hippobosca T ^ e termma ^ portion is a little wider than the rest, and 



i& usually to be seen on the .outer side, slightly separat- 



