222 
Psyche 
[September 
peripneustic system of the adult. Palmen (1877) describes 
the removal of the larval tracheal lining through the rudi- 
mentary spiracles of Ephemerida and Trichoptera. The 
rudimentary second thoracic spiracle of Pyrausta nubilalis 
Hubn. (European corn borer: Lepidoptera) functions in 
the removal of the tracheal linings from the body at pupa- 
tion. Snodgrass (1924) says that the lateral spiracles of the 
puparium of Rhagoletis are opened in the pupal stage by 
the shedding of the tracheal linings. 
The Longitudinal Trunks. 
On each side of the body is a large tracheal trunk. These 
are very large at their attachment to the walls of the 
stigmal chambers, and they taper to the anterior end of the 
body, where they divide into several smaller branches. 
Besides a gradual taper, these trunks taper abruptly at 
several places, and have somewhat the aspect of a teles- 
cope. 
These trunks represent the dorsal longitudinal trunks 
(Dt fig. 2.) , which, in the Trichoptera larvae are very much 
smaller than the ventral trunks, and which are apparently 
present only in the thorax of larval Lepidoptera. 
The ventral longitudinal trunks (Vt fig. 2) which, accord- 
ing to Snodgrass (1924), send branches to the rudimentary 
spirales in Rhagoletis, and which are connected with the 
open spiracles in Cecidomyia (Williams 1910), appear in 
Blepharipa as anastomosing branches from the large dorsal 
trunks. 
The dorsal trunks lie within the body cavity and are not 
crossed by muscles, as are the longitudinal trunks of the 
lepidopterous larvae. The ventral trunk is crossed by a 
muscle in the first abdominal segment (ml fig. 2.), and 
further investigation may show this condition present in 
the other body segments. 
Transverse Tracheae. 
Snodgrass (1924) states that in Rhagoletis the dorsal 
trunks are connected by a dorsal commissure in all segments 
