658 LAURA FLORENCE 
breaking up into innumerable tracheoles, pass through the lateral muscles _ 
and support the digestive and reproductive organs from their ventral | 
aspect. Between segments 7 and 3, eight branches are given off centrad © 
from the lateral trunks. These pass to the dorsal muscle plate, the heart 
the dorsal fat cells, and the surface of the alimentary tract. 
In some species, roots of branches extending laterad from the main 
trunks, between the branches to the stigmata of segment 3 and the thorax, 
have been described by investigators who have regarded them as vestiges 
Di} 
of branches to the lost stigmata of segments 1 and 2. Such roots have © 
not been found in this case. In the region of the second segment two | 
slender branches are given off, one laterad and the other centrad. The 
former soon bends downward and breaks into numerous tracheoles on 
the surface of the salivary glands, while the latter ramifies among the fat 
cells on the dorsal anterior region of the stomach. Under the sternite | 
of the first segment a slender branch comes off from each main trunk and 
passes to the dorsal surface of the stomach, and a second fine branch 
arises where the main tracheae bend somewhat ventrad as they ‘pass 
into the thorax. This branch breaks up in the thoracic muscie of the 
third pair of legs. 
In the thorax the main tracheae bend underneath the muscles coming | 
from the legs to the metathoracic apodeme. In line with the third pair © 
of legs a very short branch is given off laterad, from the posterior side 
of which arise two branches, une passing directly into the leg, and the 
other centrad for a short distance, when it divides into three parts. The | 
first part of this branch is the commissure of the metathoracic ganglion, 
the second ramifies on the ventral wall of the stomach, and the third 
bends laterad: passing into the leg. Opposite the second pair of legs is 
a tracheal plexus, from which spread six large branches as well as many 
small branches supplying the surrounding muscles and fat cells. A stout 
dorsal branch connects the plexus with each thoracic stigma. The first 
branch going cephalad divides, one part passing laterad to the first pair 
of legs, the other passing centrad as the commissure of the prothoracic — 
ganglion, first giving off a branch which turns backward and also enters 
the first pair of legs. The second branch going cephalad is a continuation 
of the lateral tracheal trunk and passes to the head. A branch passes 
directly centrad as the commissure of the mesothoracic ganglion, and — 
from it a branch arises at the lateral border of the ganglion and bends 
