12 RICE-PEST OF BRITISH BURMA. 



of the enclosed pupa being seen through its walls with 

 tolerable facility. There is no interval between the two 

 layers of which it would appear to be composed ; these, 

 on the contrary, being so intimately united as barely to 

 be distinguishable from one another. The last cast skin 

 of the caterpillar lies shrivelled up into a pellet in the 

 aboral end of its interior. The pupa does not lie with its 

 ventral surface directly opposite to the exposed face of 

 the cocoon, but slightly turned towards the side which is 

 to its right, and in the closest relation of apposition there- 

 with, thus leaving, on the side of the interior of the cocoon 

 to its left, a cavity into which the three nipple-shaped stig- 

 mata of its left side can be seen, through the transparent 

 walls of the cocoon, to project freely. Whether this cavity 

 contains water and the projections on which the stigmata 

 open give lodgment to a respiratory apparatus, analogous 

 to that developed in connection with the rectum in the 

 Libellulidae, for extracting oxygen from water ; or whe- 

 ther, as is more probable, it contains air, the openings on 

 the tops of the projections are stigmata leading directly 

 into the tracheal system, and the membranous walls of 

 the cocoon permit of gaseous interchange between the 

 external water and the cavity, my material is neither 

 sufficiently large nor suitable for determining. 



Explanation of the Plate. 



Fig. i. — The caterpillar, about four times the natural 

 size. 



Figs. 2, 2a, 2b. — The pupa, in three different positions, 

 five times the natural size. 



Figs. J, ja, jb. — The cocoon, from in front, from the 

 side, and from behind, respectively, five times the natural 

 size. 



