50 Annals Entomological Society of America [Vol. II, 



each side b}?" a tracheole not connected directly with the tracheal 

 system of either, but from an outside source. The tracheal sys- 

 tem of the connectives is very complete, many fine long branches 

 wind and interlace about the connectives with few free ends and 

 no anastomosis, although the long fine branches of difterent sys- 

 tems mingle very intimaetly. (Fig. B, H & 3.) 



* 



FIRST THORACIC. 



This ganglion is supplied by a transverse branch above it 

 much like that supplying the cephalic part of the previously des- 

 cribed ganglion. From this transverse branch or rather arch, 

 branches one on each side enter the ganglion laterally and a little 

 toward the head end. There are two main branches given off 

 at once on each side. On the left side the more cephalic is in 

 large part a connective branch, which divides into two at the 

 cephalic part of the ganglion; the outer of these runs up the out- 

 side of the connective for a long distance and its branches mingle 

 with those of the median independent branch of the connective. 

 The inner of the two just mentioned, runs to the point of origin 

 of the cephalic connectives and sends a somewhat smaller branch 

 along the inner side of each connective as well as a few short 

 tracheoles which turn back into the ganglion, between the con- 

 nectives. Both of these inner and outer connective branches 

 send a number of supplying tracheoles to the upper third of the 

 ganglion. On the left side the more caudal portion runs into and 

 along the edge of the ganglion, towards the caudal connectives, 

 distributing branches to the lower part of the ganglion and send- 

 ing a few short branches to the connective of its own side. On 

 the right side the larger more cephalic branch is quite different. 

 Similar parts of the ganglion are supplied b}* it as by the most 

 cephalic branch of the left side, only there seem to be more branch- 

 es and there is only one small connective twig which runs on the 

 outer side of the connective of the right side. The more caudal 

 branch of the right side is more like its fellow of the opposite side 

 in the number and position of the branches. In. addition, a large 

 recurrent portion was traced way up almost to the origin of the 

 cephalic connective of the same side. 



The above is a description of the main branches of the first 

 thoracic in a single specimen. Variations of this were found in 

 other specimens, particularly in the cephalic and caudal regions 

 of the ganglion in relation to the connectives. The supply of the 



