26 Journal New York Entomological Society. [ Voi - xxvil. 



Upon removing the dorso-longitudinal muscles of Fig. i the tra- 

 cheae shown in Fig. 2 are exposed. From spiracle I two main tubes 

 run contiguous to the dorso-ventral muscles of the mesothorax (I -II 

 b Y , I-II-b„) and each terminates at the second spiracular plexus II-p. 

 A trachea II-III-b x originates at II-p and runs dorsalward in the 

 metathorax contiguous to the dorso-ventral muscles and continues 

 over the dorsal edge of these muscles, connecting with a small air 

 sac shown in Plate III, Fig. 3, E, which in turn is indirectly united 

 with spiracle 77/. 



Upon removing the dorso-ventral muscles shown in Fig. 2 the 

 more complicated tracheal system shown in Fig. 3 is exposed. In 

 general this consists of a single principal trachea, I-II-c, which con- 

 nects spiracle I with II-p and a trachea II-III-c, which connects II-p 

 with spiracle III. In the mesothorax I-II-c gives off a ventral tube 

 which connects with the tube g shown in Fig. 1. At the middle of 

 II-III-c the main meta-thoracic trachea of Fig. 2 (II-III-b x ) after 

 passing through the air sac E joins the tracheal system of figure 3. 

 Ventrally II-III-c gives off an air sac F which connects with the sub- 

 ventral trachea w of Fig. 1. The other trachea which is given off 

 ventrally by II-III-c supplies tracheoles to the muscles. At III (Fig. 

 3) is shown a tube (tc) which runs antero-ventrally and is the origin 

 of the thoraco-cephalic trachea (tc, Fig. 1). 



In Plate IV, Fig. 7, are shown the tracheae which lie just under 

 the layer of muscles shown in Plate I, Fig. 3. but these have been 

 drawn by removing the exoskeleton of the thorax. In Fig. 3 the 

 second spiracular plexus continues ventrally and connects with the 

 main spiracular trachea, as shown in Plate II, Fig. 7. Another 

 branch from air sac D also connects with this main tube. The air 

 sacs shown in Fig. 7 will not be discussed, as reference to the figure 

 will explain their significance in supplying air to the dorso-ventral 

 muscles. From spiracle II a ventral branch is given off which soon 

 divides, sending one branch into the mesothoracic leg (i„), while the 

 other branch is connected with air sac C of Fig. I. From spiracle 

 III a branch is sent into the hind leg (I a ), while another connects 

 with, the air sac F, the other side of which has been shown in Fig. 3. 

 From the smaller chamber of spiracle I a trachea is given off which 

 runs to the fore leg and another main branch which runs to the 



