39 



tender leaves at the growing tips of the cotton plant. They 

 are very small, pale-green objects, circular in outline when 

 seen from above, and somewhat flattened as viewed from the 

 side (Fig. 34). If one is examined with a magnifying glass, 

 the surface will be seen to be marked with fine lines or 

 ridges radiating from the centre, above. The eggs are laid 

 singly not in clusters as in the case of those of many moths. 

 The duration of the egg stage is about four or five days. 



The Larva. The larva of this insect is a. caterpillar ; 

 when first hatched this is very small and of the colour of 

 the leaf. For the first few days it feeds on the epidermis 



and soft tissues on the under side 

 of the cotton leaf. As it gets 

 older, the jaws become very strong 

 and the entire tissue of the leaf 

 h eaten, except the largest veins. 

 The full-grown larva (Fig. 35) 

 measures about 1 \ inches inlength. 

 The general colour is green, with 

 a very fine bluish white line 

 running along the middle of the 

 back for the entire length of the 

 body. This is bordered on either 

 side by a broad green band, and 

 each of these in turn by one of 

 yellowish green. There are rows 

 of black spots each surrounded 

 by a white ring, and each bearing 

 in its centre a stiff hair or bristle. 



The larval stage lasts for 

 about twelve to fourteen days, 

 ordinarily, development being 

 more rapid in hot and moist 

 weather than in the cooler or drier 

 seasons. 



^ The Pupa. When the cater- 



pillar has become full-grown, it 



Fig. 35. ' Cotton worm larva, ceases feeding and transforms 



(ft) *irle ; (b) dorsal view. into the pupa, within a portion of 



Redrawn after U S Dept leaf folded over and secured by 



A.jric. (Enlarged) means of ft few gilken threads? 



forming a scant cocoon. The pupa is at first greenish in 

 colour seen changing to dark-brown ; it is about J-inch 



