48 Annals Entomological Society of America [Vol.11, 



(i) Cephalic branch, dorsal and lateral portion including 

 branches that go to the optic nerves. It divides into two main 

 parts before entering the brain, a cephalic smaller branch which 

 divides into a number of long tracheae, many of them superficial 

 and supplying the latero-cephalic portion of the brain. The larger 

 more caudal part of four or more rather large branches, for the 

 most part deep ones which supply the central part of the brain 

 and to some extent the other side. 



(2) The middle branch, supplies deep parts to some degree, 

 particularh^ in the latero-caudal region near the connective, includ- 

 ing a large trunk which runs down it nearly to the subesopha- 

 geal ganglion. On entering the l^rain this large middle branch 

 divides into a number of deep portions. 



(3) The caudal branch, gives superficial tracheae to the whole 

 mesal half of the brain and deeper ones which penetrate the ventral 

 side of the ganglion near the middle line at the caudal edge. It 

 is of two main parts, the shorter portion which divides again soon 

 into a number of branches near the middle part of the brain and 

 a longer more ventral portion. Each of these main branches on 

 running to the ventral side of the brain divides into tracheoles 

 before entering, and the larger superficial, are easily seen from the 

 ventral side, while the larger deep branches can often only be seen 

 as they turn in to send deep tracheoles to the central part of the 

 brain and smaller superficial branches to the dorsal side. The 

 large superficial ventral branches send off many fine superficial 

 tracheoles which may be seen over all parts of the brain, in some 

 degree parallel to larger when larger branches are near. 



In the center of the brain on each side, there was found a much 

 darker area due to the mass of tracheoles which formed a central 

 dense tuft. (Figs. A, G, & i & 2.) 



Following the arched nerve on each side there is a small tra- 

 cheal branch from the brain which supplies the small frontal gan- 

 glion, while on each side from some other lateral source a minute 

 lateral branch also supplies this ganglion. 



THE SUBESOPHAGEAL GAXGLIOX. 



The two pairs of branches supplying the ganglion are from 

 two sources : 



First, a ventral transverse tracheal branch of large size which 

 runs across under the ganglion and a little above it. It sends oft' 

 on each side a rather large tracheole which enters the ganglion 

 at its cephalic and ventral surface. 



