1929 ] Tracheal System of Blepharipa scutellata 223 
but the first; the first and the last being larger than the 
others, and going straight across. Williams (1910) figures 
and describes dorsal transverse tracheae in segments four 
to nine in Cecidomyia. 
In Blepharipa I found, in the anterior part of the body, 
three transverse tracheae. The first springs from a branch 
of the dorsal trunk near the point of its division into several 
branches mentioned above. The origin of this branch lies 
beneath the protractor muscles of the pharynx, and the 
trachea bends around these muscles and crosses them, and 
the posterior part of the pharynx. No branches arise 
from it. 
Rising from the opposite side of the dorsal trunk, ap- 
parantly at about the same place as the branch from which 
the transverse branch described above arises, is a branch 
which divides into three parts. The termination of the 
anterior branch I do not know. The middle branch runs 
diagonally backward above the duct of the salivary gland 
(sg fig. 2) and above the ganglia and meets a branch from 
the opposite side arising from a similar position, and having 
a similar path. This transverse commissure may send two 
branches backward to the ganglia. In one specimen ex- 
amined it apparently did so, and in another it apparently 
did not. The third branch also runs diagonally backward, 
and apparantly supplies the ganglia (br fig. 2). 
Arising from a point slightly behind one opposite the 
middle of the ganglia is another trachea which meets a 
corresponding branch from the opposite side, making the 
third of the transverse tracheae mentioned above. This 
seems a short branch forward from its junction point. 
Other transverse tracheae are probably present. 
Tracheae to the Nervous System. 
At about the line between the third thoracic and first 
abdominal segments, probably lying in the metathorax, a 
branch springs from the dorsal trunk and runs forward 
(1 fig. 2). Just anterior to its junction with the dorsal 
trunk a branch springs from it and runs beneath it toward 
the middle of the body. This branch shortly divides into six 
