48 



JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



In the dorsal part tliere are five, sometimes six, large air sacs 

 on each side. These arise at the spiracles and, witli the excep- 

 tion of the tirst, are paired. The first, as shown in Fig. 1, A, 

 is connected with a smaller air sac. In front of each pair of 

 large sacs is also a pair of smaller ones, about the same width 

 but only one-half as long as the larger and at the lower end 

 connected with the large ones by a small tube. Each large air 

 sac is also connected with the lower part of the small one 

 posterior to it. 



O T^ 



Figure 2. Ventral view of the ventral tracheal air sacs of abdomen. X3. 

 A — Main air .sacs of ventral .system. 

 B — Lateral longitudinal trachea. 

 C — Variation in number and arrangement of ventral air sacs. 



There are some variations in the arrangement of these en- 

 larged tracheal tubes. One is shown on the right side of Fig. 

 1, A, where the large air sac is in front and two smaller ones 

 lie side by side. In another instance two small air sacs are 

 connected to the first long one on the left side and there are 

 no small ones connected with the second long one. At the 

 caudal end there are several small sacs connected with each 

 other and with one spiracle, as shown in Fig. 1, A. There are 

 variations in this also, since in some a large air sac is connected 



