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BULLETIN 1397, U. S. DEPAETMEISTT OF AGRICULTUEE 



a somewhat pinkish color. It may be distinguished from the pink 

 boUworm by its habits, especially by the fact that it does not feed 

 altogether in the interior of the bolls and that it is not found 

 within the seeds. Wlien full grown it is much larger than the 

 pink bollworm, measuring about 2 inches in length. 



There is also an insect which feeds in plants known as "nigger 

 heads" {Rudheckia spp.), and another feeding in cat-tails {Typha 

 spp.), both of which are sometimes mistaken for the pink bollworm 

 {12, pp. 813, 831). The latter is especially confusing, as it is often 

 found in cotton bolls late in the season. 



The insect most likely to be mistaken for the pink bollworm is the 

 boll weevil. Although the boll weevil is sometimes found in seeds, 

 it generally is found feeding within the interior of the boll. It 

 discolors the fiber considerably, and this causes the 

 interior of the boll to assume a more or less decayed 

 appearance, quite unlike the appearance of bolls in- 

 fested by the pink bollworm, in which decay gen- 

 erally does not occur. This so-called cleanliness of 

 the work of the pink hollworin is one of the most 

 useful characteristics in differentiation. 



The accompanying illustrations will assist the 

 reader in deciding whether the work in question is 

 that of the pink bollworm or some other insect 

 found in cotton bolls. 



Figure 4 shows on the left the appearance of 

 the interior of an injured boll, and on the right 

 the characteristic small circular opening made by 

 the larva in leaving the boll or for the purpose of 

 allowing the adult to emerge. 



Figure 5 shows on the left the characteristic 

 opening made by the ordinary bollworm {Ghloridea 

 ohsoleta). It is of large size and surrounded by 

 a raised margin. The exit holes of the pink boll- 

 worm, shown on the right, are much smaller, more 

 regular, and without raised margins. 



Figure 6 shows the appearance of locks of cotton 

 (Busck ^®°^^^°®*^- bearing the typical injury caused by the pink boll- 

 worm. 

 Figure 7 shows individual seeds infested by the pink bollworm. 

 In the lower line are the " double seeds." These are frequently found 

 as the result of the webbing together of two seeds by larvae of the 

 later stages in order to obtain more room for pupation. 



Figures 8 and 9 illustrate the pink bollworm in a burr and the 

 typical opening made by this insect when it makes its way from one 

 lock to another. 



Although these descriptions may help in enabling anyone to deter- 

 Tnine whether the pink hollwx)rm. is present in a cotton field, it will 

 always be best to send^ any specimens to an entomologist for authori- 

 tative determination. It is extremely important that any possible 

 infestation by this insect be brought to attention at the earliest pos- 

 sible date, that prompt eradicative measures may be taken. 



Under the authority of the Federal Horticultural Board, August 

 Busck spent a number of months in the Hawaiian Islands in 1915 



Fig. 3. — The pink 

 bollworm : Pupa. 

 Much 



