412 COTTON 



The dark brown type is very difficult to see when spun\ 

 on the dried-up involucre of a cotton boll, and more 

 especially when on the tehl plant, as it almost exactly 

 matches its surroundings. 



Description of the Pupa (Plate I, Fig. 17). Length 

 9 mm. to 1 1 '5 mm. Head, wing, and leg cases light 

 yellowish-brown. Thorax dull blackish, with a purplish 

 tinge at the sides; in some specimens the general colour 

 of this part of the body is distinctly dull purple, as it is 

 also on the empty pupa case. There is a distinct median 

 carina on the thorax, the surface of which is much 

 roughened, the rugosities being in the form of an 

 irregular reticulate pattern. 



On the first four segments of the abdomen the dorsal, 

 surface is of a dull purplish colour, median segments, 

 paler, shading to yellowish-brown at the sides. Tip of 

 the abdomen dark and bluntly rounded. Dorsal surface 

 roughened. Ventral surface pale yellow, sometimes, 

 suffused with a greenish tinge. On each side of the fifth 

 abdominal segment posterior to the spiracle there are ; 

 a number of small brown points which stand out pro- 

 minently from the sides. These are arranged in a more 

 or less linear area, which is widest in the middle. On 

 each side of the last segment of the abdomen, and placed 

 vertically, there are generally three well-marked tooth-like 

 projections, the one nearest the dorsum being the most 

 prominent, and a series of sharp-edged ridges below them. 

 Both the teeth and the ridges appear to be variable in 

 number and distinctness, but in any case the tooth-like 

 projection nearest the dorsum is present and conspicuous. 



Length of the Pupal Stage. During the summer 

 months the pupal stage lasts from ten days to a fortnight. 

 In the late autumn and winter months it is very consider- 

 ably prolonged. Larvae which pupate at the end of 

 December or in January may remain in this stage for 

 two months or slightly more. Some boll worms which 

 pupated in the laboratory in January, 1904, gave rise to 

 the adults early in March after a quiescent period varying 

 from thirty-five to fifty-two days. 



