276 Prof. L. C. Miall and Mr. T. H. Taylor on the 
V. THE FLy. 
External Features and Segments—The mature insect is 
about 24 mm. long, the females being rather larger than 
the males. The body is black in colour. When the 
abdomen is distended the successive tergal and sternal 
plates are separated by pale-coloured intervals, and there 
is also a similar lateral band on each side. The halteres 
are white.* The abdomen of the female fly consists of 
nine segments. The Ist is seen with difficulty on the 
dorsal side, and is represented ventrally by a small plate. 
Kia. 14. 
Transverse section through 7th segment. ex, conical extension, con- 
taining retractor muscles of ovipositor, and giving attachment to the 
oblique muscles of the segment; rs, ducts of sperm-receptacles, dorsal to 
which are the rectum and the ducts of the gluten-glands. (x 115.) 
The next five segments are distinctly visible both on the 
upper and under-surface. The 7th segment differs from 
the rest in having the sternum and tergum united to 
form a short tube, into which the ovipositor can be 
retracted. The upper-front border of this tube is drawn 
out into a chitinous sheet, which extends throughout the 
segment next in front; its sides are bent downwards and 
* The rest of the description relates to the female fly only. 
