a7 
1914] Life History and Anatomy of Siphona Plusie 303 
ANATOMICAL NOTES. 
External Appearance. The larve are white and nearly 
translucent, and the colors exhibited are at either end. The 
great hooks (text-fig. 1) which form the most important 
part of the mouth structure, are jet black. On the last segment 
there are two large posterior spiracles, which are of a deep 
brown color. There are also several rows of little dark colored 
hooks around the tenth and eleventh segments (text-fig. 1). 

Fig. 1. 
Dorsal view of full grown larvae. 
Ventral view of first segment; a, antennae (?); h, great hooks. 
Dorsal view of last two segments, showing rows of little hooks and s, posterior 
spiracles. 
Lateral view of first segment; h, great hooks. 
Dorsal view of pupa. 
ie eee. 
The opening of the two large trachee at the anterior end 
are less plainly visible. The main tracheal trunks narrow to- 
wards the head, and each branches out into two fine tubes which 
terminate in small spiracular openings at about the beginning 
