INSTITUTE, PUSA, FOR 1917-18 91 



Without mid-dorsal stripe; spiracles 5 

 open or closed. 



3. Hooklets on prologs forming a com- 4 



plete circle. 

 Hooklets on prolegs forming a half- (0. S. 1560, 1574) 

 circle only. 



4. Hooklets practically equal in size . (C. S. 1674) 

 Hooklets on internal edge of sole largest (C. S. 1677) 



and gradually diminishing in size 

 externally. 



5. Spiracles open (i.e., with a clear space (C. S. 1610) 



inside). 

 Spiracle* closed (i.e., without a clear 6 

 space inside). 



6. F piracies with a slit along their major (C. S. 1561, 1580) 



axis. Hooklets on prolegs forming 

 a complete circle and all of equal 

 size. 

 Spiracles with an oval-shaped conca- (C. S. 1607, 1635) 

 vity whose major axis coincides 

 with that of spiracle. Hooklets 

 on prolegs in a more or less com- 

 plete circle but becoming shorter 

 externally. A spot in middle of 

 sole of prolegs usually present. 

 Usually with shiny large dark- 

 brown warts (absent in hibernat- 

 ing laryae). 



Key to pupal forms of Borers. 



1. Pupa without any chitinous protube- (C. S. 1801) 



ranees on anal segment. 

 Pupa with chitinous protuberances on 2 

 anal segment. 



2. Pupa without ridges or hooks on 7th (C. S. 1677) 



abdominal segment. 

 Pupa with such .... 3 



3. With complete circle of ridges, hooks, 4 



or roughness on 7th abdominal seg- 

 ment. 

 With incomplete circle as above « 5 



4. *Circle composed of distinct and sepa-(C. S. 1610) 



rate spinous hooks. 



i g2 



