534 - Prof. E. A. Minchin. Report on the [Aug. 17, 
representing the abdominal nervous system, forms the posterior-pointed 
termination of the thoracic complex. 
From each of the thoracic ganglionic centres arise two nerves, one dorsal 
and one ventral, so that altogether six pairs arise from the body of the 
thoracic complex, which are distributed to their proper regions of the thorax. 
From the posterior end of the thoracic complex arise three nerves, one 
median unpaired, and two lateral paired, which pass backwards into the 
abdomen. Cant e 
The greater part } of ‘the thorax of the fly is a mass of muscle, and as the 
muscles have to be removed in order to display the other organs in the 
thorax, the terminations and finer branches of the nerves are torn away from 
them. Hence it is impossible to describe accurately the destinations of these 
nerves without a detailed study of the musculature, which, as already stated, 
I have not made. It would appear, however, that the three ventral pairs of 
thoracic nerves innervate the legs and their muscles. 
The dorsal prothoracic nerves (fig. 1, d. pth. n.) are very slender, and, as 
already stated, form an anastomosis with the nerves from the connectives. 
The ventral prothoracic nerves (v. pth. n.) are of moderate size. 
The dorsal mesothoracic nerves (d. msth. n.) are very large, being in fact 
the stoutest nerves in the body. They run slantingly forward, then curve 
round till they run in a backward direction, and appear to be distributed to 
the wing-muscles. A small nerve arises from the ganglion close behind the 
origin of the dorsal mesothoracic nerves, and runs backwards in a dorsal 
direction, Itis drawn in fig. 1, but not lettered, and is probably to be regarded 
as a branch of the dorsal mesothoracic nerve. The ventral mesothoracic 
nerves (v. msth. n.) are also of fairly large size. 
The dorsal metathoracic nerves (d. mith. n.) are large, the ventral ones 
(v. mith. n.) of moderate size. 
The three abdominal nerves run at first straight backwards, and almost 
parallel to each other, to the waist. Before reaching it the median nerve 
(az. abd. n.) has divided into a smaller dorsal and a larger ventral branch. 
After passing through the waist the two lateral nerves (p. abd. n.) 
diverge outwards to the sides of the abdomen and break up into numerous 
branches. 
The dorsal branch of the median nerve is distributed to organs situated 
dorsally in the abdomen. The ventral branch of the median nerve is the 
nerve of the generative organs. In the male I have found that its branches 
unite to form a plexus (fig. 1, pl.), apparently containing a small ganglion, 
which gives off nerves in various directions, and from which a fairly stout 
nerve (p. n.) arises and follows the ductus ejaculatorious in its tortuous 
