296 



Mr. J. A. Doll on the Structure 



pletely brown and opaque. From the middle of each 

 segment a pair of lateral setse project, which are more 

 or less curved. There are also on all the segments 

 except the first and second numerous short, rather blunt 

 seta?, arranged in transverse bands ; there are two of these 

 bands on the third segment, and three on each of the 

 others. In the mid-dorsal line of the ninth and tenth 

 segments occur a series of black, oval, shining plates, 

 transversely elongated, but not reaching the sides of the 

 body. There are usually three on each segment, but they 

 are irregular in form and size, and occasionally one is 

 found on the eighth segment. The last or eleventh 

 segment is smooth and hard, and tapers backwards, though 



Fig. 2 ( x 80). 



Dorsal view of head of larva (to left.) ; ventral view (to right). 



the extreme tip is truncated. The anus opens on its 

 under-side, in a recess at the attached end of the segment. 

 There are two small appendages arising from the truncated 

 terminal surface of this segment. They are short, fringed 

 with setse, and somewhat like the corresponding structures 

 in the Pcricoma larva, but not so much developed. As in 

 Pcricoma, the larva? can hang from the surface-film by 

 means of the anal appendages. If depressed beneath the 

 surface, the anal appendages do not carry down a bubble 

 of air, with which the spiracles communicate, as in the 

 Pcricoma larva, though small air bubbles often adhere to 

 the seta?. When floating at the surface, the larva, if it is 

 able to reach the bottom, can drag itself along by means 



